old_contents: class MergeError(Exception):
      """An error for when merging two branches fails."""
      pass
  
  
  class PushError(Exception):
      """An error for when pushing a branch to upstream fails."""
      pass
  
  
  class OptionsCheckError(Exception):
      """
      An error that represents when command-line options were used
      inappropriately for the given SCMClient backend. The message in the
      exception is presented to the user.
      """
      pass
  
  
  class InvalidRevisionSpecError(Exception):
      """An error for when the specified revisions are invalid."""
      pass
  
  
  class MinimumVersionError(Exception):
      """An error for when software doesn't meet version requirements."""
      pass
  
  
  class TooManyRevisionsError(InvalidRevisionSpecError):
      """An error for when too many revisions were specified."""
      def __init__(self):
          super(TooManyRevisionsError, self).__init__(
              'Too many revisions specified')
  
  
  class EmptyChangeError(Exception):
      def __init__(self):
          super(EmptyChangeError, self).__init(
              "Couldn't find any affected files for this change.")
  
new_contents: from __future__ import unicode_literals
  
  
  class MergeError(Exception):
      """An error for when merging two branches fails."""
  
  
  class PushError(Exception):
      """An error for when pushing a branch to upstream fails."""
  
  
  class OptionsCheckError(Exception):
      """An error for when command-line options are used incorrectly."""
  
  
  class InvalidRevisionSpecError(Exception):
      """An error for when the specified revisions are invalid."""
  
  
  class MinimumVersionError(Exception):
      """An error for when software doesn't meet version requirements."""
  
  
  class TooManyRevisionsError(InvalidRevisionSpecError):
      """An error for when too many revisions were specified."""
  
      def __init__(self):
          super(TooManyRevisionsError, self).__init__(
              'Too many revisions specified')
  
  
  class EmptyChangeError(Exception):
      """An error for when there are no changed files."""
  
      def __init__(self):
          super(EmptyChangeError, self).__init__(
              "Couldn't find any affected files for this change.")
  
subject: Clean up the rbtools.clients.errors module