<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _extract(__func__, kwds, keys, classname, probe=True):
 """ Used by decorators stochastic and deterministic to inspect declarations """


    # Add docs and name
    kwds['doc'] = __func__.__doc__
    if not 'name' in kwds:
        kwds['name'] = __func__.__name__
    # kwds.update({'doc':__func__.__doc__, 'name':__func__.__name__})

    # Instanitate dictionary of parents
    parents = {}

    # This gets used by stochastic to check for long-format logp and random:
    if probe:
        cur_status = check_special_methods()
        disable_special_methods()
        # Define global tracing function (I assume this is for debugging??)
        # No, it's to get out the logp and random functions, if they're in
        # there.

        def probeFunc(frame, event, arg):
            if event == 'return':
                locals = frame.f_locals
                kwds.update(dict((k, locals.get(k)) for k in keys))
                sys.settrace(None)
            return probeFunc

        sys.settrace(probeFunc)

        # Get the functions logp and random (complete interface).
        # Disable special methods to prevent the formation of a hurricane of
        # Deterministics
        try:
            __func__()
        except:
            if 'logp' in keys:
                kwds['logp'] = __func__
            else:
                kwds['eval'] = __func__
        # Reenable special methods.
        if cur_status:
            enable_special_methods()

    for key in keys:
        if not key in kwds:
            kwds[key] = None

    for key in ['logp', 'eval']:
        if key in keys:
            if kwds[key] is None:
                kwds[key] = __func__

    # Build parents dictionary by parsing the __func__tion's arguments.
    (args, defaults) = get_signature(__func__)

    if defaults is None:
        defaults = ()

    # Make sure all parents were defined
    arg_deficit = (len(args) - ('value' in args)) - len(defaults)
    if arg_deficit > 0:
        err_str =  classname + ' ' + __func__.__name__ + \
            ': no parent provided for the following labels:'
        for i in range(arg_deficit):
            err_str += " " + args[i + ('value' in args)]
            if i < arg_deficit - 1:
                err_str += ','
        raise ValueError(err_str)

    # Fill in parent dictionary
    try:
        parents.update(dict(zip(args[-len(defaults):], defaults)))
    except TypeError:
        pass

    value = parents.pop('value', None)

    return (value, parents)