def histogram_voltage(self, timestep=None, title=True, **kwargs):
        """
        Plots histogram of voltages.

        For more information see :func:`edisgo.tools.plots.histogram`.

        Parameters
        ----------
        timestep : :pandas:`pandas.Timestamp<timestamp>` or None, optional
            Specifies time step histogram is plotted for. If timestep is None
            all time steps voltages are calculated for are used. Default: None.
        title : :obj:`str` or :obj:`bool`, optional
            Title for plot. If True title is auto generated. If False plot has
            no title. If :obj:`str`, the provided title is used. Default: True.

        """
        data = self.network.results.v_res()
        if title is True:
            if timestep is not None:
                title = "Voltage histogram for time step {}".format(timestep)
            else:
                title = "Voltage histogram \nfor time steps {} to {}".format(
                    data.index[0], data.index[-1])
        elif title is False:
            title = None
        plots.histogram(data=data, title=title, timeindex=timestep, **kwargs)
Plots histogram of voltages.

        For more information see :func:`edisgo.tools.plots.histogram`.

        Parameters
        ----------
        timestep : :pandas:`pandas.Timestamp<timestamp>` or None, optional
            Specifies time step histogram is plotted for. If timestep is None
            all time steps voltages are calculated for are used. Default: None.
        title : :obj:`str` or :obj:`bool`, optional
            Title for plot. If True title is auto generated. If False plot has
            no title. If :obj:`str`, the provided title is used. Default: True.