def update_value(self, uid, **kwargs):
        """
        Updates contact's custom field value.
        Returns :class:`Contact` object contains id and link to Contact.

        :Example:

        client.custom_fields.update_value(uid=1900901, contact_id=192012, value="abc")

        :param int uid:        The unique id of the CustomField to update a value. Required.
        :param int contactId:  The unique id of the Contact to update value. Required.
        :param str value:      Value of CustomField. Required.
        """
        contacts = Contacts(self.base_uri, self.auth)
        return self.update_subresource_instance(uid, body=kwargs,
                                                subresource=contacts,
                                                slug="update")