Add a Priority to the project and returns a :class:`Priority` object.

        :param name: name of the :class:`Priority`
        :param attrs: optional attributes for :class:`Priority`

def add_priority(self, name, **attrs):
        """
        Add a Priority to the project and returns a :class:`Priority` object.

        :param name: name of the :class:`Priority`
        :param attrs: optional attributes for :class:`Priority`
        """
        return Priorities(self.requester).create(self.id, name, **attrs)