def METHOD_NAME(data):
    """Check that there is a valid schema and all FtM conform to it."""
    schema = model.get(data.get("schema"))
    if schema is None:
        raise InvalidData(gettext("No schema on entity"))
    # This isn't strictly required because the proxy will contain
    # only those values that can be inserted for each property,
    # making it valid -- all this does, therefore, is to raise an
    # exception that notifies the user.
    schema.validate(data)