def check_tracer_for_mass_profile(func):
@wraps(func)<EOL>def wrapper(self):<EOL><INDENT>"""<STR_LIT>"""<EOL>if self.has_mass_profile is True:<EOL><INDENT>return func(self)<EOL><DEDENT>else:<EOL><INDENT>return None<EOL><DEDENT><DEDENT>return wrapper<EOL>
If none of the tracer's galaxies have a mass profile, it surface density, potential and deflections cannot \
    be computed. This wrapper makes these properties return *None*.

    Parameters
    ----------
    func : (self) -> Object
        A property function that requires galaxies to have a mass profile.