code: def keep(self, *cols):
          
          try:
              self.df = self.df[list(cols)]
          except Exception as e:
              self.err(e, "Can not remove colums")
              return
          self.ok("Setting dataframe to columns", " ".join(cols))
docs: Limit the dataframe to some columns
  
          :param cols: names of the columns
          :type cols: str
  
          :example: ``ds.keep("Col 1", "Col 2")``