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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 is_json(string):
 """ Check if a string is a valid json. :param string: String to check. :type string: str :return: True if json, false otherwise :rtype: bool """

    if not is_full_string(string):
        return False
    if bool(JSON_WRAPPER_RE.search(string)):
        try:
            return isinstance(json.loads(string), dict)
        except (TypeError, ValueError, OverflowError):
            return False
    return False