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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 add_initial(initial_input):
 """ Constructs a stateful object for handling vensim's 'Initial' functionality Parameters initial_input: basestring The expression which will be evaluated, and the first value of which returned Returns ------- reference: basestring reference to the Initial object `__call__` method, which will return the first calculated value of `initial_input` new_structure: list list of element construction dictionaries for the builder to assemble """

    stateful = {
        'py_name': utils.make_python_identifier('_initial_%s' % initial_input)[0],
        'real_name': 'Smooth of %s' % initial_input,
        'doc': 'Returns the value taken on during the initialization phase',
        'py_expr': 'functions.Initial(lambda: %s)' % (
            initial_input),
        'unit': 'None',
        'lims': 'None',
        'eqn': 'None',
        'subs': '',
        'kind': 'stateful',
        'arguments': ''
    }

    return "%s()" % stateful['py_name'], [stateful]