old_contents: from logging import Logger
  from ..loggers import StructuredLogger
  from ..loggers import PropagationLogger
  from ..loggers import TrackingLogger
  
  
  class LoggersFactory(object):
  
      @staticmethod
      def make(structured_logger=False,
               propagation_logger=False,
               tracking_logger=False):
  
          # fix for python 2.6 compatibility
          class XYZ(object):
              pass
  
          import sys
          if sys.version.startswith('2.6'):
              setattr(Logger.__bases__[0], '__mro__', object)
  
          cls_list = []
          if structured_logger:
              cls_list.append(StructuredLogger)
          if propagation_logger:
              cls_list.append(PropagationLogger)
          if tracking_logger:
              cls_list.append(TrackingLogger)
          if not len(cls_list):
              cls_list.extend([Logger, XYZ])
          return type('MixedLogger', tuple(cls_list), {})
  
new_contents: from logging import Logger
  from ..loggers import StructuredLogger
  from ..loggers import PropagationLogger
  from ..loggers import TrackingLogger
  
  
  class LoggersFactory(object):
  
      @staticmethod
      def make(structured_logger=False,
               propagation_logger=False,
               tracking_logger=False):
  
          # fix for python 2.6 compatibility
          class XYZ(object):
              pass
  
          import sys
          if sys.version.startswith('2.6'):
              setattr(Logger.__bases__[0], '__mro__', object)
  
          cls_list = []
          if structured_logger:
              cls_list.append(StructuredLogger)
          if propagation_logger:
              cls_list.append(PropagationLogger)
          if tracking_logger:
              cls_list.append(TrackingLogger)
          if not len(cls_list):
              cls_list.append(Logger)
          cls_list.append(XYZ)
          return type('MixedLogger', tuple(cls_list), {})
  
subject: fix mixed factory for python 2.6 (#5)