def potential(__func__=None, **kwds):
    """
    Decorator function instantiating potentials. Usage:

    @potential
    def B(parent_name = ., ...)
        return baz(parent_name, ...)

    where baz returns the deterministic B's value conditional
    on its parents.

    :SeeAlso:
      Deterministic, deterministic, Stochastic, Potential, stochastic, data, Model
    """
    def instantiate_pot(__func__):
        junk, parents = _extract(
            __func__, kwds, keys, 'Potential', probe=False)
        return Potential(parents=parents, **kwds)

    keys = ['logp']

    instantiate_pot.kwds = kwds

    if __func__:
        return instantiate_pot(__func__)

    return instantiate_pot