code: def histogram_month_counts(
      df,
      variable
      ):
      
      if not df.index.dtype in ["datetime64[ns]", "<M8[ns]", ">M8[ns]"]:
          log.error("index is not datetime")
          return False
      counts = df.groupby(df.index.strftime("%B"))[variable].count().reindex(calendar.month_name[1:])
      counts.plot(kind = "bar", width = 1, rot = 0, alpha = 0.7)
docs: Create a year-long histogram of counts of the variable for each month. It is
      assumed that the DataFrame index is datetime and that the variable
      `month_name` exists.