code: def _get_override_base(self, override_wrapper):
          
          base = override_wrapper.modifier.base
          if not base:
              return None
          if is_class(base):
              return base
  
          # resolve the (possibly qualified) class name
          if '.' in base:
              # repeatedly try to import the first N-1, N-2, etc. dot-separated
              # parts of the qualified name; this way we can handle all names
              # including `package.module.Class.InnerClass`
              dot_parts = base.split('.')
              for i in xrange(len(dot_parts) - 1, 1, -1):  # n-1 -> 1
                  module_name = '.'.join(dot_parts[:i])
                  class_name = '.'.join(dot_parts[i:])
                  try:
                      module = __import__(module_name, fromlist=[dot_parts[i]])
                      break
                  except ImportError:
                      pass
              else:
                  # couldn't resolve class name, return it verbatim
                  return base
          else:
              class_name = base
              module_name = override_wrapper.method.__module__
              module = sys.modules[module_name]
  
          return getattr(module, class_name)
docs: Retrieve the override base class from the
          :class:`_OverriddenMethod` wrapper.