'Encodes the value using DER
:param force:
If the encoded contents already exist, clear them and regenerate
to ensure they are in DER format instead of BER format
:return:
A byte string of the DER-encoded value'

def dump(self, force=False):

    self.contents = self.chosen.dump(force=force)
    if ((self._header is None) or force):
        if (self.tag_type == u'explicit'):
            self._header = _dump_header(self.explicit_class, 1, self.explicit_tag, self.contents)
        else:
            self._header = ''
    return (self._header + self.contents)
