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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def as_manager(cls, obj):
 """ Convert obj into TaskManager instance. Accepts string, filepath, dictionary, `TaskManager` object. If obj is None, the manager is initialized from the user config file. """

        if isinstance(obj, cls): return obj
        if obj is None: return cls.from_user_config()

        if is_string(obj):
            if os.path.exists(obj):
                return cls.from_file(obj)
            else:
                return cls.from_string(obj)

        elif isinstance(obj, collections.abc.Mapping):
            return cls.from_dict(obj)
        else:
            raise TypeError("Don't know how to convert type %s to TaskManager" % type(obj))