submodules are specified (when the submodule already has
          qconfig attribute). Entries in the dictionary need to be
          QConfig instances.
    * A set of types and/or submodule names to apply dynamic
      quantization to, in which case the *dtype* argument is used
      to specify the bit-width

  * **inplace** -- carry out model transformations in-place, the
    original module is mutated

  * **mapping** -- maps type of a submodule to a type of
    corresponding dynamically quantized version with which the
    submodule needs to be replaced
