export tutorials changed in c161138 (#498)

Co-authored-by: dario-coscia <dario-coscia@users.noreply.github.com>

tutorials/tutorial9/tutorial.ipynb

@@ -35,11 +35,11 @@
     "    !pip install \"pina-mathlab\"\n",
     "\n",
     "import torch\n",
-    "import matplotlib.pyplot as plt \n",
+    "import matplotlib.pyplot as plt\n",
     "import warnings\n",
     "\n",
     "from pina import Condition, Trainer\n",
-    "from pina.problem import SpatialProblem \n",
+    "from pina.problem import SpatialProblem\n",
     "from pina.operator import laplacian\n",
     "from pina.model import FeedForward\n",
     "from pina.model.block import PeriodicBoundaryEmbedding  # The PBC module\n",

tutorials/tutorial9/tutorial.py

@@ -14,7 +14,7 @@
 #
 # First of all, some useful imports.
 
-# In[14]:
+# In[ ]:
 
 
 ## routine needed to run the notebook on Google Colab