code: def set_attr(self, **kwargs):
          
          for key, value in kwargs.items():
              if value is not None:
                  if not isinstance(value, STRING_TYPES):
                      raise ValueError("Set Attr only accepts string values")
                  value = c_str(str(value))
              _check_call(_LIB.XGBoosterSetAttr(
                  self.handle, c_str(key), value))
docs: Set the attribute of the Booster.
  
          Parameters
          ----------
          **kwargs
              The attributes to set. Setting a value to None deletes an attribute.