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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_phens(phen_grid, **kwargs):
 """ Plots circles colored according to the values in phen_grid. -1 serves as a sentinel value, indicating that a circle should not be plotted in that location. """

    denom, palette = get_kwargs(phen_grid, kwargs, True)

    grid = color_grid(phen_grid, palette, denom)

    for i in range(len(grid)):
        for j in range(len(grid[i])):
            if grid[i][j] != -1 and tuple(grid[i][j]) != -1:
                plt.gca().add_patch(plt.Circle((j, i),
                                    radius=.3, lw=1, ec="black",
                                    facecolor=grid[i][j], zorder=2))