Read the Field from the file-like object `fio`.

        .. note::

            Advanced usage only. You will typically never need to call this
            method as it will be called for you when loading a ClassFile.

        :param source: Any file-like object providing `read()`

def unpack(self, source: IO):
        """
        Read the Field from the file-like object `fio`.

        .. note::

            Advanced usage only. You will typically never need to call this
            method as it will be called for you when loading a ClassFile.

        :param source: Any file-like object providing `read()`
        """
        self.access_flags.unpack(source.read(2))
        self._name_index, self._descriptor_index = unpack('>HH', source.read(4))
        self.attributes.unpack(source)