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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 polyplot(df, projection=None, extent=None, figsize=(8, 6), ax=None, edgecolor='black', facecolor='None', **kwargs):
 """ Trivial polygonal plot. Parameters df : GeoDataFrame The data being plotted. projection : geoplot.crs object instance, optional A geographic projection. For more information refer to `the tutorial page on projections <https://nbviewer.jupyter.org/github/ResidentMario/geoplot/blob/master/notebooks/tutorials/Projections.ipynb>`_. extent : None or (minx, maxx, miny, maxy), optional Used to control plot x-axis and y-axis limits manually. figsize : tuple, optional An (x, y) tuple passed to ``matplotlib.figure`` which sets the size, in inches, of the resultant plot. Defaults to (8, 6), the ``matplotlib`` default global. figsize : tuple, optional An (x, y) tuple passed to ``matplotlib.figure`` which sets the size, in inches, of the resultant plot. ax : AxesSubplot or GeoAxesSubplot instance, optional A ``matplotlib.axes.AxesSubplot`` or ``cartopy.mpl.geoaxes.GeoAxesSubplot`` instance. Defaults to a new axis. kwargs: dict, optional Keyword arguments to be passed to the underlying ``matplotlib`` `Polygon patches <http://matplotlib.org/api/patches_api.html#matplotlib.patches.Polygon>`_. Returns ------- ``AxesSubplot`` or ``GeoAxesSubplot`` The plot axis Examples -------- The polyplot can be used to draw simple, unembellished polygons. A trivial example can be created with just a geometry and, optionally, a projection. .. code-block:: python import geoplot as gplt import geoplot.crs as gcrs gplt.polyplot(boroughs, projection=gcrs.AlbersEqualArea()) .. image:: ../figures/polyplot/polyplot-initial.png However, note that ``polyplot`` is mainly intended to be used in concert with other plot types. .. code-block:: python ax = gplt.polyplot(boroughs, projection=gcrs.AlbersEqualArea()) gplt.pointplot(collisions[collisions['BOROUGH'].notnull()], projection=gcrs.AlbersEqualArea(), hue='BOROUGH', categorical=True, legend=True, edgecolor='white', linewidth=0.5, legend_kwargs={'loc': 'upper left'}, ax=ax) .. image:: ../figures/polyplot/polyplot-stacked.png Additional keyword arguments are passed to the underlying ``matplotlib`` `Polygon patches <http://matplotlib.org/api/patches_api.html#matplotlib.patches.Polygon>`_. .. code-block:: python ax = gplt.polyplot(boroughs, projection=gcrs.AlbersEqualArea(), linewidth=0, facecolor='lightgray') .. image:: ../figures/polyplot/polyplot-kwargs.png """

    # Initialize the figure.
    fig = _init_figure(ax, figsize)

    if projection:
        # Properly set up the projection.
        projection = projection.load(df, {
            'central_longitude': lambda df: np.mean(np.array([p.x for p in df.geometry.centroid])),
            'central_latitude': lambda df: np.mean(np.array([p.y for p in df.geometry.centroid]))
        })

        # Set up the axis.
        if not ax:
            ax = plt.subplot(111, projection=projection)

    else:
        if not ax:
            ax = plt.gca()

    # Clean up patches.
    _lay_out_axes(ax, projection)

    # Immediately return if input geometry is empty.
    if len(df.geometry) == 0:
        return ax

    # Set extent.
    extrema = _get_envelopes_min_maxes(df.geometry.envelope.exterior)
    _set_extent(ax, projection, extent, extrema)

    # Finally we draw the features.
    if projection:
        for geom in df.geometry:
            features = ShapelyFeature([geom], ccrs.PlateCarree())
            ax.add_feature(features, facecolor=facecolor, edgecolor=edgecolor, **kwargs)
    else:
        for geom in df.geometry:
            try:  # Duck test for MultiPolygon.
                for subgeom in geom:
                    feature = descartes.PolygonPatch(subgeom, facecolor=facecolor, edgecolor=edgecolor, **kwargs)
                    ax.add_patch(feature)
            except (TypeError, AssertionError):  # Shapely Polygon.
                feature = descartes.PolygonPatch(geom, facecolor=facecolor, edgecolor=edgecolor, **kwargs)
                ax.add_patch(feature)

    return ax