code: def mode(self, saveMode):
          
          # At the JVM side, the default value of mode is already set to "error".
          # So, if the given saveMode is None, we will not call JVM-side's mode method.
          if saveMode is not None:
              self._jwrite = self._jwrite.mode(saveMode)
          return self
docs: Specifies the behavior when data or table already exists.
  
          Options include:
  
          * `append`: Append contents of this :class:`DataFrame` to existing data.
          * `overwrite`: Overwrite existing data.
          * `error` or `errorifexists`: Throw an exception if data already exists.
          * `ignore`: Silently ignore this operation if data already exists.
  
          >>> df.write.mode('append').parquet(os.path.join(tempfile.mkdtemp(), 'data'))