def plot_gross_leverage(returns, positions, ax=None, **kwargs):
if ax is None:<EOL><INDENT>ax = plt.gca()<EOL><DEDENT>gl = timeseries.gross_lev(positions)<EOL>gl.plot(lw=<NUM_LIT:0.5>, color='<STR_LIT>', legend=False, ax=ax, **kwargs)<EOL>ax.axhline(gl.mean(), color='<STR_LIT:g>', linestyle='<STR_LIT>', lw=<NUM_LIT:3>)<EOL>ax.set_title('<STR_LIT>')<EOL>ax.set_ylabel('<STR_LIT>')<EOL>ax.set_xlabel('<STR_LIT>')<EOL>return ax<EOL>
Plots gross leverage versus date.

Gross leverage is the sum of long and short exposure per share
divided by net asset value.

Parameters
----------
returns : pd.Series
    Daily returns of the strategy, noncumulative.
     - See full explanation in tears.create_full_tear_sheet.
positions : pd.DataFrame
    Daily net position values.
     - See full explanation in create_full_tear_sheet.
ax : matplotlib.Axes, optional
    Axes upon which to plot.
**kwargs, optional
    Passed to plotting function.

Returns
-------
ax : matplotlib.Axes
    The axes that were plotted on.