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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_tcoords(array, coords, scantypes=None, ax=None, **kwargs):
 """Plot coordinates related to the time axis. Args: array (xarray.DataArray):
 Array which the coodinate information is included. coords (list):
 Name of x axis and y axis. scantypes (list):
 Scantypes. If None, all scantypes are used. ax (matplotlib.axes):
 Axis you want to plot on. kwargs (optional):
 Plot options passed to ax.plot(). """

    if ax is None:
        ax = plt.gca()

    if scantypes is None:
        ax.plot(array[coords[0]], array[coords[1]], label='ALL', **kwargs)
    else:
        for scantype in scantypes:
            ax.plot(array[coords[0]][array.scantype == scantype],
                    array[coords[1]][array.scantype == scantype], label=scantype, **kwargs)
    ax.set_xlabel(coords[0])
    ax.set_ylabel(coords[1])
    ax.set_title('{} vs {}'.format(coords[1], coords[0]))
    ax.legend()

    logger.info('{} vs {} has been plotted.'.format(coords[1], coords[0]))