chore: Fix precision-recall plots for the cases of 1 and 2 classes

ssd300_evaluation.ipynb

@@ -401,7 +401,7 @@
  }
  ],
  "source": [
- "m = (n_classes + 1) // 2\n",
+ "m = max((n_classes + 1) // 2, 2)\n",
  "n = 2\n",
  "\n",
  "fig, cells = plt.subplots(m, n, figsize=(n*8,m*8))\n",