code: def iterfiles(service, name=None, mimeType=SHEET, order=FILEORDER):
      
      params = {'orderBy': order, 'pageToken': None}
      q = []
      if name is not None:
          q.append("name='%s'" % name)
      if mimeType is not None:
          q.append("mimeType='%s'" % mimeType)
      if q:
          params['q'] = ' and '.join(q)
  
      while True:
          response = service.files().list(**params).execute()
          for f in response['files']:
              yield f['id'], f['name']
          try:
              params['pageToken'] = response['nextPageToken']
          except KeyError:
              return
docs: Fetch and yield ``(id, name)`` pairs for Google drive files.