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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 _infer_x_for_line(y):
 """ Infers the x for a line if no x is provided. """

    array_shape = shape(y)

    if len(array_shape) == 0:
        return []
    if len(array_shape) == 1:
        return arange(array_shape[0])
    if len(array_shape) > 1:
        return arange(array_shape[1])