code: def get_group_for_col(self, table_name, col_name):
          
          df = self.dm[table_name]
          try:
              group_name = df.loc[col_name, 'group']
          except KeyError:
              return ''
          return group_name
docs: Check data model to find group name for a given column header
  
          Parameters
          ----------
          table_name: str
          col_name: str
  
          Returns
          ---------
          group_name: str