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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 convert_string(string):
 """Convert string to int, float or bool. """

    if is_int(string):
        return int(string)
    elif is_float(string):
        return float(string)
    elif convert_bool(string)[0]:
        return convert_bool(string)[1]
    elif string == 'None':
        return None
    else:
        return string