PYTHON-962 - NotImplemented instead of NotImplementedError

Author: aherlihy

pymongo/read_preferences.py

@@ -119,7 +119,7 @@ def __eq__(self, other):
  if isinstance(other, _ServerMode):
  return (self.mode == other.mode and
  self.tag_sets == other.tag_sets)
- raise NotImplementedError
+ return NotImplemented
 
  def __ne__(self, other):
  return not self == other
@@ -161,7 +161,7 @@ def __repr__(self):
  def __eq__(self, other):
  if isinstance(other, _ServerMode):
  return other.mode == _PRIMARY
- raise NotImplementedError
+ return NotImplemented
 
 
 class PrimaryPreferred(_ServerMode):