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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 extract_variables(content):
 """ extract all variables in content recursively. """

    if isinstance(content, (list, set, tuple)):
        variables = set()
        for item in content:
            variables = variables | extract_variables(item)
        return variables

    elif isinstance(content, dict):
        variables = set()
        for key, value in content.items():
            variables = variables | extract_variables(value)
        return variables

    elif isinstance(content, LazyString):
        return set(regex_findall_variables(content.raw_string))

    return set()