def tolist(self, fill_value=None):
if fill_value is not None:<EOL><INDENT>return self.filled(fill_value).tolist()<EOL><DEDENT>result = narray(self.filled().tolist(), dtype=object)<EOL>mask = narray(self._mask.tolist())<EOL>result[mask] = None<EOL>return result.tolist()<EOL>
Copy the data portion of the array to a hierarchical python
        list and returns that list.

        Data items are converted to the nearest compatible Python
        type.  Masked values are converted to fill_value. If
        fill_value is None, the corresponding entries in the output
        list will be ``None``.