Warns user that fields defined in Meta.fields or Meta.additional will
    be ignored

    :param dict fields: A dictionary of fields name field object pairs
    :param Meta: the schema's Meta class

def warn_if_fields_defined_in_meta(fields, Meta):
    """Warns user that fields defined in Meta.fields or Meta.additional will
    be ignored

    :param dict fields: A dictionary of fields name field object pairs
    :param Meta: the schema's Meta class
    """
    if getattr(Meta, "fields", None) or getattr(Meta, "additional", None):
        declared_fields = set(fields.keys())
        if (
            set(getattr(Meta, "fields", set())) > declared_fields
            or set(getattr(Meta, "additional", set())) > declared_fields
        ):
            warnings.warn(
                "Only explicitly-declared fields will be included in the Schema Object. "
                "Fields defined in Meta.fields or Meta.additional are ignored."
            )