docs: def delete(self, record_key):
          
          ''' a method to delete a record from S3
  
          :param record_key: string with key of record
          :return: string reporting outcome
          '''
      
          title = '%s.delete' % self.__class__.__name__
      
      # validate inputs
          input_fields = {
              'record_key': record_key
          }
          for key, value in input_fields.items():
              object_title = '%s(%s=%s)' % (title, key, str(value))
              self.fields.validate(value, '.%s' % key, object_title)
      
      # delete record
          try:
              self.s3.delete_record(self.bucket_name, record_key)
          except:
              if not self.exists(record_key):
                  exit_msg = '%s does not exist.' % record_key
                  return exit_msg
              raise
          
          exit_msg = '%s has been deleted.' % record_key
          return exit_msg