code: def attach(self, file):
          
          try:
              result = self.get_one()
              if 'sys_id' not in result:
                  raise NoResults()
          except MultipleResults:
              raise MultipleResults('Attaching a file to multiple records is not supported')
          except NoResults:
              raise NoResults('Attempted to attach file to a non-existing record')
  
          if not os.path.isfile(file):
              raise InvalidUsage("Attachment '%s' must be an existing regular file" % file)
  
          response = self.session.post(
              self._get_attachment_url('upload'),
              data={
                  'table_name': self.table,
                  'table_sys_id': result['sys_id'],
                  'file_name': ntpath.basename(file)
              },
              files={'file': open(file, 'rb')},
              headers={'content-type': None}  # Temporarily override header
          )
          return self._get_content(response)
docs: Attaches the queried record with `file` and returns the response after validating the response
  
          :param file: File to attach to the record
          :raise:
              :NoResults: if query returned no results
              :MultipleResults: if query returned more than one result (currently not supported)
          :return:
              - The attachment record metadata