code: def _remove_leading_dots_for_smtp_transparency_support(self, input_data):
          
          regex = re.compile('^\.\.', re.MULTILINE)
          data_without_transparency_dots = regex.sub('.', input_data)
          return re.sub('\r\n', '\n', data_without_transparency_dots)
docs: Uses the input data to recover the original payload (includes
          transparency support as specified in RFC 821, Section 4.5.2).