Grouped histogram

    Parameters
    ----------
    data : Series/DataFrame
    column : object, optional
    by : object, optional
    ax : axes, optional
    bins : int, default 50
    figsize : tuple, optional
    layout : optional
    sharex : bool, default False
    sharey : bool, default False
    rot : int, default 90
    grid : bool, default True
    kwargs : dict, keyword arguments passed to matplotlib.Axes.hist

    Returns
    -------
    collection of Matplotlib Axes

def grouped_hist(data, column=None, by=None, ax=None, bins=50, figsize=None,
                 layout=None, sharex=False, sharey=False, rot=90, grid=True,
                 xlabelsize=None, xrot=None, ylabelsize=None, yrot=None,
                 **kwargs):
    """
    Grouped histogram

    Parameters
    ----------
    data : Series/DataFrame
    column : object, optional
    by : object, optional
    ax : axes, optional
    bins : int, default 50
    figsize : tuple, optional
    layout : optional
    sharex : bool, default False
    sharey : bool, default False
    rot : int, default 90
    grid : bool, default True
    kwargs : dict, keyword arguments passed to matplotlib.Axes.hist

    Returns
    -------
    collection of Matplotlib Axes
    """
    _raise_if_no_mpl()
    _converter._WARN = False

    def plot_group(group, ax):
        ax.hist(group.dropna().values, bins=bins, **kwargs)

    xrot = xrot or rot

    fig, axes = _grouped_plot(plot_group, data, column=column,
                              by=by, sharex=sharex, sharey=sharey, ax=ax,
                              figsize=figsize, layout=layout, rot=rot)

    _set_ticks_props(axes, xlabelsize=xlabelsize, xrot=xrot,
                     ylabelsize=ylabelsize, yrot=yrot)

    fig.subplots_adjust(bottom=0.15, top=0.9, left=0.1, right=0.9,
                        hspace=0.5, wspace=0.3)
    return axes