dict which defines the global variables when stmt is being
        executed. This is the other method for providing variables
        which stmt needs.
  * **label** (*Optional**[**str**]*) -- String which summarizes
    *stmt*. For instance, if *stmt* is
    "torch.nn.functional.relu(torch.add(x, 1, out=out))" one might
    set label to "ReLU(x + 1)" to improve readability.

  * **sub_label** (*Optional**[**str**]*) --

    Provide supplemental information to disambiguate measurements
    with identical stmt or label. For instance, in our example
    above sub_label might be "float" or "int", so that it is easy
    to differentiate: "ReLU(x + 1): (float)"

    "ReLU(x + 1): (int)" when printing Measurements or summarizing
    using *Compare*.

  * **description** (*Optional**[**str**]*) --

    String to distinguish measurements with identical label and
    sub_label. The principal use of *description* is to signal to
