meter and return a scalar. If None (default), 'scott'
          is used.

        data : indexable object, optional
            DATA_PARAMETER_PLACEHOLDER

        Returns
        -------
        dict
          A dictionary mapping each component of the violinplot to a
          list of the corresponding collection instances created. The
          dictionary has the following keys:

          - ``bodies``: A list of the `~.collections.PolyCollection`
            instances containing the filled area of each violin.

          - ``cmeans``: A `~.collections.LineCollection` instance that marks
            the mean values of each of the violin's distribution.

          - ``cmins``: A `~.collections.LineCollection` instance that marks
            the bottom of each violin's distribution.

          - ``cmaxes``: A `~.collections.LineCollection` instance that marks
            the top of each violin's distribution.

          - ``cbars``: A `~.collections.LineCollection` instance that marks
            the centers of each violin's distribution.

          - ``cmedians``: A `~.collections.LineCollection` instance that
            marks the median values of each of the violin's distribution.

          - ``cquantiles``: A `~.collections.LineCollection` instance created
            to identify the quantile values of each of the violin's
            distribution.

        c