code: def _parse_file(cls, value):
          
          include_directive = 'file:'
  
          if not isinstance(value, string_types):
              return value
  
          if not value.startswith(include_directive):
              return value
  
          spec = value[len(include_directive):]
          filepaths = (os.path.abspath(path.strip()) for path in spec.split(','))
          return '\n'.join(
              cls._read_file(path)
              for path in filepaths
              if (cls._assert_local(path) or True)
              and os.path.isfile(path)
          )
docs: Represents value as a string, allowing including text
          from nearest files using `file:` directive.
  
          Directive is sandboxed and won't reach anything outside
          directory with setup.py.
  
          Examples:
              file: README.rst, CHANGELOG.md, src/file.txt
  
          :param str value:
          :rtype: str