code: def process_columns(self, columns):
          
          if type(columns) == list:
              self.columns = columns
          elif type(columns) == str:
              self.columns = [c.strip() for c in columns.split()]
          elif type(columns) == IntEnum:
              self.columns = [str(c) for c in columns]
          else:
              raise RawlException("Unknown format for columns")
docs: Handle provided columns and if necessary, convert columns to a list for 
          internal strage.
  
          :columns: A sequence of columns for the table. Can be list, comma
              -delimited string, or IntEnum.