Import string or return object.

        :params value: Import path or class object to instantiate.
        :params default: Default object to return if the import fails.
        :returns: The imported object.

def load_obj_or_import_string(self, value):
        """Import string or return object.

        :params value: Import path or class object to instantiate.
        :params default: Default object to return if the import fails.
        :returns: The imported object.
        """
        imp = self.app.config.get(value)
        if isinstance(imp, six.string_types):
            return import_string(imp)
        elif imp:
            return imp