@fields.setter<EOL><INDENT>def fields(self, fields):<DEDENT>
self._fields = fields<EOL>
Setter for fields. If set to None this reader yields each row from the source as a list. If set to a list of
field names this reader yields each row from the source as a dictionary using the given field names.

:param list[str]|None fields: The fields (or columns) that must be read from the source.