Handle filter sets
        :param app: Flask application

def _handle_filter_sets(self, app):
        """
        Handle filter sets
        :param app: Flask application
        """
        if 'IMAGINE_FILTER_SETS' in app.config and isinstance(app.config['IMAGINE_FILTER_SETS'], dict):
            for filter_name, filters_settings in app.config['IMAGINE_FILTER_SETS'].items():
                filter_set = []
                if isinstance(filters_settings, dict) and 'filters' in filters_settings:
                    for filter_type, filter_settings in filters_settings['filters'].items():
                        if filter_type in self._filters:
                            filter_item = self._filters[filter_type](**filter_settings)
                            if isinstance(filter_item, ImagineFilterInterface):
                                filter_set.append(filter_item)
                            else:
                                raise ValueError('Filter must be implement ImagineFilterInterface')
                        else:
                            raise ValueError('Unknown filter type: %s' % filter_type)

                    filter_config = {'filters': filter_set}
                    if 'cached' in filters_settings:
                        filter_config['cached'] = filters_settings['cached']
                    else:
                        filter_config['cached'] = app.config['IMAGINE_CACHE_ENABLED']

                    self._filter_sets.update({filter_name: filter_config})
                else:
                    raise ValueError('Wrong settings for filter: %s' % filter_name)
        else:
            raise ValueError('Filters configuration does not present')