Fix various import issues

[etc/taskwarrior.git] / tasklib / backends.py

diff --git a/tasklib/backends.py b/tasklib/backends.py
index 2a00deeb56d32649d2ff136f059b06803ece9233..edf9ac3eeca32526b95ae3dc8e837dc87fd9c830 100644 (file)
--- a/tasklib/backends.py
+++ b/tasklib/backends.py
@@ -1,10 +1,16 @@
 import abc
+import datetime
 import json
 import os
 import re
+import six
 import subprocess
 
-from tasklib.filters import TaskWarriorFilter
+from .task import Task, TaskQuerySet
+from .filters import TaskWarriorFilter
+from .serializing import local_zone
+
+DATE_FORMAT_CALC = '%Y-%m-%dT%H:%M:%S'
 
 VERSION_2_1_0 = six.u('2.1.0')
 VERSION_2_2_0 = six.u('2.2.0')
@@ -19,7 +25,10 @@ VERSION_2_4_5 = six.u('2.4.5')
 
 class Backend(object):
 
-    filter_class = TaskWarriorFilter
+    @abc.abstractproperty
+    def filter_class(self):
+        """Returns the TaskFilter class used by this backend"""
+        pass
 
     @abc.abstractmethod
     def filter_tasks(self, filter_obj):
@@ -205,6 +214,10 @@ class TaskWarrior(object):
                              "datetime, its type is not supported: {}"
                              .format(type(value)))
 
+    @property
+    def filter_class(self):
+        return TaskWarriorFilter
+
     # Public interface
 
     def get_config(self):