code: def plot_counts(df, theme):
      
      dates, counts = df['date-observation'], df[theme + "_count"]
      fig, ax = plt.subplots()
      ax.set_ylabel("{} pixel counts".format(" ".join(theme.split("_"))))
      ax.set_xlabel("observation date")
      ax.plot(dates, counts, '.')
      fig.autofmt_xdate()
      plt.show()
docs: plot the counts of a given theme from a created database over time