Intended for internal use only, this function is used in diffnet_index
methods.
diffnet_check_attr_class(value, meta)
Arguments
value: Either a matrix, data frame or a list. Attribute values.
meta: A list. A diffnet object's meta data.
Returns
The value object either as a data frame (if static) or as a list of data frames (if dynamic). If value does not follows the permitted types of diffnet_index, then returns with error.