code: def validate_min_itemsize(self, min_itemsize):
          
          if min_itemsize is None:
              return
          if not isinstance(min_itemsize, dict):
              return
  
          q = self.queryables()
          for k, v in min_itemsize.items():
  
              # ok, apply generally
              if k == 'values':
                  continue
              if k not in q:
                  raise ValueError(
                      "min_itemsize has the key [{key}] which is not an axis or "
                      "data_column".format(key=k))
docs: validate the min_itemisze doesn't contain items that are not in the
          axes this needs data_columns to be defined