code: def pivot_hist(self, pivot_column_label, value_column_label, overlay=True, width=6, height=4, **vargs):
          
          warnings.warn("pivot_hist is deprecated; use "
                        "hist(value_column_label, group=pivot_column_label), or "
                        "with side_by_side=True if you really want side-by-side "
                        "bars.")
          pvt_labels = np.unique(self[pivot_column_label])
          pvt_columns = [self[value_column_label][np.where(self[pivot_column_label] == pivot)] for pivot in pvt_labels]
          n = len(pvt_labels)
          colors = list(itertools.islice(itertools.cycle(self.chart_colors), n))
          if overlay:
              plt.figure(figsize=(width, height))
              vals, bins, patches = plt.hist(pvt_columns, color=colors, **vargs)
              plt.legend(pvt_labels)
          else:
              _, axes = plt.subplots(n, 1, figsize=(width, height * n))
              vals = []
              bins = None
              for axis, label, column, color in zip(axes, pvt_labels, pvt_columns, colors):
                  if isinstance(bins, np.ndarray):
                      avals, abins, patches = axis.hist(column, color=color, bins=bins, **vargs)
                  else:
                      avals, abins, patches = axis.hist(column, color=color, **vargs)
                  axis.set_xlabel(label, fontsize=16)
                  vals.append(avals)
                  if not isinstance(bins, np.ndarray):
                      bins = abins
                  else:
                      assert bins.all() == abins.all(), "Inconsistent bins in hist"
          t = type(self)()
          t['start'] = bins[0:-1]
          t['end'] = bins[1:]
          for label, column in zip(pvt_labels,vals):
              t[label] = column
docs: Draw histograms of each category in a column.