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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 iter_symbols(code):
 """Yield names and strings used by `code` and its nested code objects"""

    for name in code.co_names:
        yield name
    for const in code.co_consts:
        if isinstance(const, six.string_types):
            yield const
        elif isinstance(const, CodeType):
            for name in iter_symbols(const):
                yield name