Update basic_graphs.py (TheAlgorithms#1990)

* Update basic_graphs.py

missing return statement line no:223.

* Update basic_graphs.py

Co-authored-by: vinayak <itssvinayak@gmail.com>

Author: karthikeyansa

graphs/basic_graphs.py

@@ -220,6 +220,7 @@ def prim(G, s):
                 if v[1] < dist.get(v[0], 100000):
                     dist[v[0]] = v[1]
                     path[v[0]] = u
+    return dist
 
 
 """