<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _convert(cls, name, module, filter, source=None):
 """ Create a new Enum subclass that replaces a collection of global constants """

    # convert all constants from source (or module) that pass filter() to
    # a new Enum called name, and export the enum and its members back to
    # module;
    # also, replace the __reduce_ex__ method so unpickling works in
    # previous Python versions
    module_globals = vars(_sys.modules[module])
    if source:
        source = vars(source)
    else:
        source = module_globals
    members = dict((name, value) for name, value in source.items() if filter(name))
    cls = cls(name, members, module=module)
    cls.__reduce_ex__ = _reduce_ex_by_name
    module_globals.update(cls.__members__)
    module_globals[name] = cls
    return cls