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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 fetch_processed_single_clause(element: "ClauseElement", compiler: "SQLCompiler") -> str: """ Takes a clause element that must have a single clause, and converts it to raw SQL text. """

    if len(element.clauses) != 1:
        raise TypeError("Only one argument supported; {} were passed".format(
            len(element.clauses)))
    clauselist = element.clauses  # type: ClauseList
    first = clauselist.get_children()[0]
    return compiler.process(first)