docs: def export(self, storage_client, overwrite=True):
          
          '''
              a method to export all the records in collection to another platform
              
          :param storage_client: class object with storage client methods
          :return: string with exit message
          '''
          
          title = '%s.export' % self.__class__.__name__
          
      # validate storage client
          method_list = [ 'save', 'load', 'list', 'export', 'delete', 'remove', '_import', 'collection_name' ]
          for method in method_list:
              if not getattr(storage_client, method, None):
                  from labpack.parsing.grammar import join_words
                  raise ValueError('%s(storage_client=...) must be a client object with %s methods.' % (title, join_words(method_list)))
              
      # walk collection folder to find files
          import os
          count = 0
          skipped = 0
          for file_path, file_id in self._walk():
              path_segments = file_path.split(os.sep)
              record_key = os.path.join(*path_segments)
              record_key = record_key.replace('\\','/')
              
      # retrieve data and metadata
              try:
                  record_data = self.drive.get_media(fileId=file_id).execute()
              except:
                  raise DriveConnectionError(title)
              try:
                  file = self.drive.get(fileId=file_id, fields='modifiedTime').execute()
                  client_modified = file.get('modifiedTime', '')
              except:
                  raise DriveConnectionError(title)
              
      # import record into storage client
              last_modified = 0.0
              if client_modified:
                  from labpack.records.time import labDT
                  last_modified = labDT.fromISO(client_modified).epoch()
              outcome = storage_client._import(record_key, record_data, overwrite=overwrite, last_modified=last_modified)
              if outcome:
                  count += 1
              else:
                  skipped += 1
              
      # report outcome
          plural = ''
          skip_insert = ''
          new_folder = storage_client.collection_name
          if count != 1:
              plural = 's'
          if skipped > 0:
              skip_plural = ''
              if skipped > 1:
                  skip_plural = 's'
              skip_insert = ' %s record%s skipped to avoid overwrite.' % (str(skipped), skip_plural)
          exit_msg = '%s record%s exported to %s.%s' % (str(count), plural, new_folder, skip_insert)
          return exit_msg