def _get_search_fields(model):
    """
    Get search fields from a model
    :param model: Model object
    :return: Return list of fields otherwise return None
    """
    search_fields = []
    field_types = ['Slugfield', 'Foreignkey']
    fields_names = ['object_id', 'content_object', 'time_created', 'last_update', 'id']
    try:
        if model:
            for field in model._meta.get_fields():
                verbose_name = getattr(field, 'verbose_name', None)
                if verbose_name:
                    field_name = str(field.name)
                    field_type = str(field.get_internal_type().title())
                    if field_name not in fields_names and field_type not in field_types:
                        search_fields.append(field_name)
            return search_fields
    except AssertionError:
        return None