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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 _format_date_param(params, key, format="%Y-%m-%d %H:%M:%S"):
 """ Utility function to convert datetime values to strings. If the value is already a str, or is not in the dict, no change is made. :param params: A `dict` of params that may contain a `datetime` value. :param key: The datetime value to be converted to a `str` :param format: The `strftime` format to be used to format the date. The default value is '%Y-%m-%d %H:%M:%S' """

    if key in params:
        param = params[key]
        if hasattr(param, "strftime"):
            params[key] = param.strftime(format)