code: def rename_column(self, column, new_name):
          
          if type(column) is not str: column = self.ckeys[column]
          self.ckeys[self.ckeys.index(column)] = new_name
          self.columns[new_name] = self.columns.pop(column)
          return self
docs: This will rename the column.
          The supplied column can be an integer or the old column name.