diff --git a/src/documents/actions.py b/src/documents/actions.py
index 3db5cd314..cd2698a2c 100644
--- a/src/documents/actions.py
+++ b/src/documents/actions.py
@@ -4,10 +4,13 @@ from django.contrib.admin.utils import model_ngettext
 from django.core.exceptions import PermissionDenied
 from django.template.response import TemplateResponse
 
-from documents.models import Tag, Correspondent
+from documents.models import Correspondent, Tag
 
 
-def select_action(modeladmin, request, queryset, title, action, modelclass, success_message="", document_action=None, queryset_action=None):
+def select_action(
+        modeladmin, request, queryset, title, action, modelclass,
+        success_message="", document_action=None, queryset_action=None):
+
     opts = modeladmin.model._meta
     app_label = opts.app_label
 
@@ -27,7 +30,9 @@ def select_action(modeladmin, request, queryset, title, action, modelclass, succ
                 queryset_action(queryset, selected_object)
 
             modeladmin.message_user(request, success_message % {
-                "selected_object": selected_object.name, "count": n, "items": model_ngettext(modeladmin.opts, n)
+                "selected_object": selected_object.name,
+                "count": n,
+                "items": model_ngettext(modeladmin.opts, n)
             }, messages.SUCCESS)
 
         # Return None to display the change list page again.
@@ -47,10 +52,17 @@ def select_action(modeladmin, request, queryset, title, action, modelclass, succ
 
     request.current_app = modeladmin.admin_site.name
 
-    return TemplateResponse(request, "admin/%s/%s/select_object.html" % (app_label, opts.model_name), context)
+    return TemplateResponse(
+        request,
+        "admin/{}/{}/select_object.html".format(app_label, opts.model_name),
+        context
+    )
 
 
-def simple_action(modeladmin, request, queryset, success_message="", document_action=None, queryset_action=None):
+def simple_action(
+        modeladmin, request, queryset, success_message="",
+        document_action=None, queryset_action=None):
+
     if not modeladmin.has_change_permission(request):
         raise PermissionDenied
 
@@ -72,37 +84,63 @@ def simple_action(modeladmin, request, queryset, success_message="", document_ac
 
 
 def add_tag_to_selected(modeladmin, request, queryset):
-    return select_action(modeladmin=modeladmin, request=request, queryset=queryset,
-                         title="Add tag to multiple documents",
-                         action="add_tag_to_selected",
-                         modelclass=Tag,
-                         success_message="Successfully added tag %(selected_object)s to %(count)d %(items)s.",
-                         document_action=lambda doc, tag: doc.tags.add(tag))
-add_tag_to_selected.short_description = "Add tag to selected documents"
+    return select_action(
+        modeladmin=modeladmin,
+        request=request,
+        queryset=queryset,
+        title="Add tag to multiple documents",
+        action="add_tag_to_selected",
+        modelclass=Tag,
+        success_message="Successfully added tag %(selected_object)s to "
+                        "%(count)d %(items)s.",
+        document_action=lambda doc, tag: doc.tags.add(tag)
+    )
 
 
 def remove_tag_from_selected(modeladmin, request, queryset):
-    return select_action(modeladmin=modeladmin, request=request, queryset=queryset,
-                         title="Remove tag from multiple documents",
-                         action="remove_tag_from_selected",
-                         modelclass=Tag,
-                         success_message="Successfully removed tag %(selected_object)s from %(count)d %(items)s.",
-                         document_action=lambda doc, tag: doc.tags.remove(tag))
-remove_tag_from_selected.short_description = "Remove tag from selected documents"
+    return select_action(
+        modeladmin=modeladmin,
+        request=request,
+        queryset=queryset,
+        title="Remove tag from multiple documents",
+        action="remove_tag_from_selected",
+        modelclass=Tag,
+        success_message="Successfully removed tag %(selected_object)s from "
+                        "%(count)d %(items)s.",
+        document_action=lambda doc, tag: doc.tags.remove(tag)
+    )
 
 
 def set_correspondent_on_selected(modeladmin, request, queryset):
-    return select_action(modeladmin=modeladmin, request=request, queryset=queryset,
-                         title="Set correspondent on multiple documents",
-                         action="set_correspondent_on_selected",
-                         modelclass=Correspondent,
-                         success_message="Successfully set correspondent %(selected_object)s on %(count)d %(items)s.",
-                         queryset_action=lambda qs, correspondent: qs.update(correspondent=correspondent))
-set_correspondent_on_selected.short_description = "Set correspondent on selected documents"
+
+    return select_action(
+        modeladmin=modeladmin,
+        request=request,
+        queryset=queryset,
+        title="Set correspondent on multiple documents",
+        action="set_correspondent_on_selected",
+        modelclass=Correspondent,
+        success_message="Successfully set correspondent %(selected_object)s "
+                        "on %(count)d %(items)s.",
+        queryset_action=lambda qs, corr: qs.update(correspondent=corr)
+    )
 
 
 def remove_correspondent_from_selected(modeladmin, request, queryset):
-    return simple_action(modeladmin=modeladmin, request=request, queryset=queryset,
-                         success_message="Successfully removed correspondent from %(count)d %(items)s.",
-                         queryset_action=lambda qs: qs.update(correspondent=None))
-remove_correspondent_from_selected.short_description = "Remove correspondent from selected documents"
+    return simple_action(
+        modeladmin=modeladmin,
+        request=request,
+        queryset=queryset,
+        success_message="Successfully removed correspondent from %(count)d "
+                        "%(items)s.",
+        queryset_action=lambda qs: qs.update(correspondent=None)
+    )
+
+
+add_tag_to_selected.short_description = "Add tag to selected documents"
+remove_tag_from_selected.short_description = \
+    "Remove tag from selected documents"
+set_correspondent_on_selected.short_description = \
+    "Set correspondent on selected documents"
+remove_correspondent_from_selected.short_description = \
+    "Remove correspondent from selected documents"
diff --git a/src/documents/admin.py b/src/documents/admin.py
index d545c1c02..365a99c1a 100644
--- a/src/documents/admin.py
+++ b/src/documents/admin.py
@@ -3,21 +3,23 @@ from datetime import datetime, timedelta
 from django.conf import settings
 from django.contrib import admin, messages
 from django.contrib.admin.templatetags.admin_urls import add_preserved_filters
-from django.contrib.auth.models import User, Group
+from django.contrib.auth.models import Group, User
+from django.db import models
 from django.http import HttpResponseRedirect
-try:
-    from django.core.urlresolvers import reverse
-except ImportError:
-    from django.urls import reverse
 from django.templatetags.static import static
+from django.urls import reverse
 from django.utils.html import format_html, format_html_join
 from django.utils.http import urlquote
 from django.utils.safestring import mark_safe
-from django.db import models
 
-from documents.actions import add_tag_to_selected, remove_tag_from_selected, set_correspondent_on_selected, \
-    remove_correspondent_from_selected
-from .models import Correspondent, Tag, Document, Log
+from documents.actions import (
+    add_tag_to_selected,
+    remove_correspondent_from_selected,
+    remove_tag_from_selected,
+    set_correspondent_on_selected
+)
+
+from .models import Correspondent, Document, Log, Tag
 
 
 class FinancialYearFilter(admin.SimpleListFilter):
@@ -92,11 +94,18 @@ class RecentCorrespondentFilter(admin.RelatedFieldListFilter):
         self.title = "correspondent (recent)"
 
     def field_choices(self, field, request, model_admin):
+
+        years = settings.PAPERLESS_RECENT_CORRESPONDENT_YEARS
+        days = 365 * years
+
         lookups = []
-        if settings.PAPERLESS_RECENT_CORRESPONDENT_YEARS and settings.PAPERLESS_RECENT_CORRESPONDENT_YEARS > 0:
-            date_limit = datetime.now() - timedelta(days=365*settings.PAPERLESS_RECENT_CORRESPONDENT_YEARS)
-            for c in Correspondent.objects.filter(documents__created__gte=date_limit).distinct():
+        if years and years > 0:
+            correspondents = Correspondent.objects.filter(
+                documents__created__gte=datetime.now() - timedelta(days=days)
+            ).distinct()
+            for c in correspondents:
                 lookups.append((c.id, c.name))
+
         return lookups
 
 
@@ -106,13 +115,22 @@ class CommonAdmin(admin.ModelAdmin):
 
 class CorrespondentAdmin(CommonAdmin):
 
-    list_display = ("name", "match", "matching_algorithm", "document_count", "last_correspondence")
+    list_display = (
+        "name",
+        "match",
+        "matching_algorithm",
+        "document_count",
+        "last_correspondence"
+    )
     list_filter = ("matching_algorithm",)
     list_editable = ("match", "matching_algorithm")
 
     def get_queryset(self, request):
         qs = super(CorrespondentAdmin, self).get_queryset(request)
-        qs = qs.annotate(document_count=models.Count("documents"), last_correspondence=models.Max("documents__created"))
+        qs = qs.annotate(
+            document_count=models.Count("documents"),
+            last_correspondence=models.Max("documents__created")
+        )
         return qs
 
     def document_count(self, obj):
@@ -152,17 +170,29 @@ class DocumentAdmin(CommonAdmin):
     readonly_fields = ("added",)
     list_display = ("title", "created", "added", "thumbnail", "correspondent",
                     "tags_")
-    list_filter = ("tags", ('correspondent', RecentCorrespondentFilter), "correspondent", FinancialYearFilter)
+    list_filter = (
+        "tags",
+        ("correspondent", RecentCorrespondentFilter),
+        "correspondent",
+        FinancialYearFilter
+    )
 
     filter_horizontal = ("tags",)
 
     ordering = ["-created", "correspondent"]
 
-    actions = [add_tag_to_selected, remove_tag_from_selected, set_correspondent_on_selected, remove_correspondent_from_selected]
+    actions = [
+        add_tag_to_selected,
+        remove_tag_from_selected,
+        set_correspondent_on_selected,
+        remove_correspondent_from_selected
+    ]
 
-    date_hierarchy = 'created'
+    date_hierarchy = "created"
 
-    document_queue = None
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.document_queue = []
 
     def has_add_permission(self, request):
         return False
@@ -172,25 +202,38 @@ class DocumentAdmin(CommonAdmin):
     created_.short_description = "Created"
 
     def changelist_view(self, request, extra_context=None):
-        response = super().changelist_view(request, extra_context)
 
-        if request.method == 'GET':
+        response = super().changelist_view(
+            request,
+            extra_context=extra_context
+        )
+
+        if request.method == "GET":
             cl = self.get_changelist_instance(request)
             self.document_queue = [doc.id for doc in cl.queryset]
 
         return response
 
-    def change_view(self, request, object_id=None, form_url='', extra_context=None):
+    def change_view(self, request, object_id=None, form_url='',
+                    extra_context=None):
+
         extra_context = extra_context or {}
-        doc = Document.objects.get(id=object_id)
-        if self.document_queue and object_id and int(object_id) in self.document_queue:
-            # There is a queue of documents
-            current_index = self.document_queue.index(int(object_id))
-            if current_index < len(self.document_queue) - 1:
-                # ... and there are still documents in the queue
-                extra_context['next_object'] = self.document_queue[current_index + 1]
+
+        if self.document_queue and object_id:
+            if int(object_id) in self.document_queue:
+                # There is a queue of documents
+                current_index = self.document_queue.index(int(object_id))
+                if current_index < len(self.document_queue) - 1:
+                    # ... and there are still documents in the queue
+                    extra_context["next_object"] = self.document_queue[
+                        current_index + 1
+                    ]
+
         return super(DocumentAdmin, self).change_view(
-            request, object_id, form_url, extra_context=extra_context,
+            request,
+            object_id,
+            form_url,
+            extra_context=extra_context,
         )
 
     def response_change(self, request, obj):
@@ -200,25 +243,35 @@ class DocumentAdmin(CommonAdmin):
         preserved_filters = self.get_preserved_filters(request)
 
         msg_dict = {
-            'name': opts.verbose_name,
-            'obj': format_html('<a href="{}">{}</a>', urlquote(request.path), obj),
+            "name": opts.verbose_name,
+            "obj": format_html(
+                '<a href="{}">{}</a>',
+                urlquote(request.path),
+                obj
+            ),
         }
         if "_saveandeditnext" in request.POST:
             msg = format_html(
-                'The {name} "{obj}" was changed successfully. Editing next object.',
+                'The {name} "{obj}" was changed successfully. '
+                'Editing next object.',
                 **msg_dict
             )
             self.message_user(request, msg, messages.SUCCESS)
-            redirect_url = reverse('admin:%s_%s_change' %
-                                   (opts.app_label, opts.model_name),
-                                   args=(request.POST['_next_object'],),
-                                   current_app=self.admin_site.name)
-            redirect_url = add_preserved_filters({'preserved_filters': preserved_filters, 'opts': opts}, redirect_url)
-            response = HttpResponseRedirect(redirect_url)
-        else:
-            response = super().response_change(request, obj)
+            redirect_url = reverse(
+                "admin:{}_{}_change".format(opts.app_label, opts.model_name),
+                args=(request.POST["_next_object"],),
+                current_app=self.admin_site.name
+            )
+            redirect_url = add_preserved_filters(
+                {
+                    "preserved_filters": preserved_filters,
+                    "opts": opts
+                },
+                redirect_url
+            )
+            return HttpResponseRedirect(redirect_url)
 
-        return response
+        return super().response_change(request, obj)
 
     @mark_safe
     def thumbnail(self, obj):
diff --git a/src/documents/templates/admin/documents/document/select_object.html b/src/documents/templates/admin/documents/document/select_object.html
index 1439b5c21..775d57b12 100644
--- a/src/documents/templates/admin/documents/document/select_object.html
+++ b/src/documents/templates/admin/documents/document/select_object.html
@@ -1,46 +1,50 @@
 {% extends "admin/base_site.html" %}
+
+
 {% load i18n l10n admin_urls static %}
 {% load staticfiles %}
 
-{% block extrahead %}
-{{ block.super }}
-{{ media }}
-<script type="text/javascript" src="{% static 'admin/js/cancel.js' %}"></script>
 
+{% block extrahead %}
+	{{ block.super }}
+	{{ media }}
+	<script type="text/javascript" src="{% static 'admin/js/cancel.js' %}"></script>
 {% endblock %}
 
+
 {% block bodyclass %}{{ block.super }} app-{{ opts.app_label }} model-{{ opts.model_name }} delete-confirmation delete-selected-confirmation{% endblock %}
 
+
 {% block breadcrumbs %}
-<div class="breadcrumbs">
-    <a href="{% url 'admin:index' %}">{% trans 'Home' %}</a>
-    &rsaquo; <a href="{% url 'admin:app_list' app_label=opts.app_label %}">{{ opts.app_config.verbose_name }}</a>
-    &rsaquo; <a href="{% url opts|admin_urlname:'changelist' %}">{{ opts.verbose_name_plural|capfirst }}</a>
-    &rsaquo; {{title}}
-</div>
+	<div class="breadcrumbs">
+		<a href="{% url 'admin:index' %}">{% trans 'Home' %}</a>
+		&rsaquo; <a href="{% url 'admin:app_list' app_label=opts.app_label %}">{{ opts.app_config.verbose_name }}</a>
+		&rsaquo; <a href="{% url opts|admin_urlname:'changelist' %}">{{ opts.verbose_name_plural|capfirst }}</a>
+		&rsaquo; {{ title }}
+	</div>
 {% endblock %}
 
 {% block content %}
-<p>Please select the {{itemname}}.</p>
-<form method="post">{% csrf_token %}
-    <div>
-        {% for obj in queryset %}
-        <input type="hidden" name="{{ action_checkbox_name }}" value="{{ obj.pk|unlocalize }}"/>
-        {% endfor %}
-        <p>
-            <select name="obj_id">
-                {% for obj in objects %}
-                <option value="{{obj.id}}">{{obj.name}}</option>
-                {% endfor %}
-            </select>
-        </p>
+	<p>Please select the {{itemname}}.</p>
+	<form method="post">{% csrf_token %}
+		<div>
+			{% for obj in queryset %}
+			<input type="hidden" name="{{ action_checkbox_name }}" value="{{ obj.pk|unlocalize }}"/>
+			{% endfor %}
+			<p>
+				<select name="obj_id">
+					{% for obj in objects %}
+					<option value="{{ obj.id }}">{{ obj.name }}</option>
+					{% endfor %}
+				</select>
+			</p>
 
-        <input type="hidden" name="action" value="{{action}}"/>
-        <input type="hidden" name="post" value="yes"/>
-        <p>
-            <input type="submit" value="{% trans "Confirm" %}" />
-            <a href="#" class="button cancel-link">{% trans "Go back" %}</a>
-        </p>
-    </div>
-</form>
+			<input type="hidden" name="action" value="{{ action }}"/>
+			<input type="hidden" name="post" value="yes" />
+			<p>
+				<input type="submit" value="{% trans 'Confirm' %}" />
+				<a href="#" class="button cancel-link">{% trans "Go back" %}</a>
+			</p>
+		</div>
+	</form>
 {% endblock %}
diff --git a/src/paperless/settings.py b/src/paperless/settings.py
index e6f3da0cb..433eabe88 100644
--- a/src/paperless/settings.py
+++ b/src/paperless/settings.py
@@ -81,7 +81,7 @@ INSTALLED_APPS = [
 
     "rest_framework",
     "crispy_forms",
-    "django_filters"
+    "django_filters",
 
 ]