code: def add_column(self, col, values=None):
      self._columns.append(col)
  
      if values is None:
          values = []
      # update records
      if len(self._records) > 0:
          for rec in self._records:
              if len(values) > 0:
                  value = values.pop(0)
              else:
                  value = None
              rec.append(value)
  
imports: import copy
  import pandas
  from mindsdb.api.executor.exceptions import WrongArgumentError
label_desc: Use image node_id 9 for calling the ResultSet obj's underlying member method code with example usage: obj.add_column(col, values) without return types