def METHOD_NAME(self, unknown, datatype):
    """
    Reinitializes the named unknown quantity, making it of the given
    data type.
    """
    if unknown not in self.unknowns:
        return
    attr = {}
    u = self.unknowns[unknown]
    if 'description' in u.__dict__:
        attr['description'] = u.description
    if 'description_eqn' in u.__dict__:
        attr['equation'] = u.description_eqn
    self.setUnknown(name=unknown, data=u.data, attr=attr, datatype=datatype)