code: def parse_config(file_name='smarterling.config'):
      
      if not os.path.exists(file_name) or not os.path.isfile(file_name):
          raise SmarterlingError('Config file not found: %s' % file_name)
      try:
          contents = read_from_file(file_name)
          contents_with_environment_variables_expanded = os.path.expandvars(contents)
          return AttributeDict(yaml.load(contents_with_environment_variables_expanded))
      except Exception as e:
          raise SmarterlingError("Error paring config file: %s" % str(e))
docs: Parses a smarterling configuration file