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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 tco_return_handle(tokens):
 """Process tail-call-optimizable return statements."""

    internal_assert(len(tokens) == 2, "invalid tail-call-optimizable return statement tokens", tokens)
    if tokens[1].startswith("()"):
        return "return _coconut_tail_call(" + tokens[0] + ")" + tokens[1][2:]  # tokens[1] contains \n
    else:
        return "return _coconut_tail_call(" + tokens[0] + ", " + tokens[1][1:]