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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 FindFirst(params, ctxt, scope, stream, coord, interp):
 """ This function is identical to the FindAll function except that the return value is the position of the first occurrence of the target found. A negative number is returned if the value could not be found. """

    global FIND_MATCHES_ITER
    FIND_MATCHES_ITER = _find_helper(params, ctxt, scope, stream, coord, interp)

    try:
        first = six.next(FIND_MATCHES_ITER)
        return first.start() + FIND_MATCHES_START_OFFSET
    except StopIteration as e:
        return -1