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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 camel_to_snake_case(string):
 """Converts 'string' presented in camel case to snake case. e.g.: CamelCase => snake_case """

    s = _1.sub(r'\1_\2', string)
    return _2.sub(r'\1_\2', s).lower()