code: def plot_phens(phen_grid, **kwargs):
      
      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))
docs: 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.