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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def plot_sino(self, ax=None, Ang=_def.LOSImpAng, AngUnit=_def.LOSImpAngUnit, Sketch=True, dP=None, dLeg=_def.TorLegd, draw=True, fs=None, wintit=None, Test=True):
 """ Plot the sinogram of the vessel polygon, by computing its envelopp in a cross-section, can also plot a 3D version of it The envelop of the polygon is computed using self.Sino_RefPt as a reference point in projection space, and plotted using the provided dictionary of properties. Optionaly a small sketch can be included illustrating how the angle and the impact parameters are defined (if the axes is not provided). Parameters proj : str Flag indicating whether to plot a classic sinogram ('Cross') from the vessel cross-section (assuming 2D) or an extended 3D version '3d' of it with additional angle ax : None or plt.Axes The axes on which the plot should be done, if None a new figure and axes is created Ang : str Flag indicating which angle to use for the impact parameter, the angle of the line itself (xi) or of its impact parameter (theta) AngUnit : str Flag for the angle units to be displayed, 'rad' for radians or 'deg' for degrees Sketch : bool Flag indicating whether a small skecth showing the definitions of angles 'theta' and 'xi' should be included or not Pdict : dict Dictionary of properties used for plotting the polygon envelopp, fed to plt.plot() if proj='Cross' and to plt.plot_surface() if proj='3d' LegDict : None or dict Dictionary of properties used for plotting the legend, fed to plt.legend(), the legend is not plotted if None draw : bool Flag indicating whether the fig.canvas.draw() shall be called automatically a4 : bool Flag indicating whether the figure should be plotted in a4 dimensions for printing Test : bool Flag indicating whether the inputs shall be tested for conformity Returns ------- ax : plt.Axes The axes used to plot """

        if Test:
            msg = "The impact parameters must be set ! (self.set_dsino())"
            assert not self.dsino['RefPt'] is None, msg

        # Only plot cross sino, from version 1.4.0
        dP = _def.TorPFilld if dP is None else dP
        ax = _plot.Plot_Impact_PolProjPoly(self, ax=ax, Ang=Ang,
                                           AngUnit=AngUnit, Sketch=Sketch,
                                           Leg=self.Id.NameLTX, dP=dP,
                                           dLeg=dLeg, draw=False,
                                           fs=fs, wintit=wintit, Test=Test)
        # else:
        # Pdict = _def.TorP3DFilld if Pdict is None else Pdict
        # ax = _plot.Plot_Impact_3DPoly(self, ax=ax, Ang=Ang, AngUnit=AngUnit,
                                      # Pdict=Pdict, dLeg=LegDict, draw=False,
                                      # fs=fs, wintit=wintit, Test=Test)
        if draw:
            ax.figure.canvas.draw()
        return ax