[pre-commit.ci] auto fixes from pre-commit.com hooks

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examples/intro/checking_validity_of_a_pag.py

@@ -57,9 +57,9 @@
 # %%
 # Validity of a PAG
 # ---------------------------
-# For a PAG to be valid, it must represent a valid 
+# For a PAG to be valid, it must represent a valid
 # equivalent class of MAGs. This can be verified by
-# turning the PAG into an MAG and then checking the 
+# turning the PAG into an MAG and then checking the
 # validity of the MAG
 # To check if the constructed PAG is a valid one in
 # pywhy-graphs, we can simply do:
@@ -74,7 +74,7 @@
 # a single mark in the graph such that the PAG
 # does not represent the equivalent class of MAGs:
 
-pag.remove_edge("S","I",pag.circle_edge_name)
+pag.remove_edge("S", "I", pag.circle_edge_name)
 
 # returns False
 print(pywhy_graphs.valid_pag(pag))