docs(frontend): making an Alphabet class

frontends/concrete-python/examples/levenshtein_distance/levenshtein_distance.py

@@ -81,7 +81,7 @@ def compile_module(self, args):
             min_max_strategy_preference=fhe.MinMaxStrategy.ONE_TLU_PROMOTED,
         )
 
-    def check_string_is_in_alphabet(string):
+    def check_string_is_in_alphabet(self, string):
         """Check a string is a valid string of an alphabet."""
         assert len(self.mapping_to_int) > 0, "Mapping not defined"
 
@@ -341,7 +341,7 @@ def main():
     # Do what the user requested
     if args.autotest:
         myalphabet = Alphabet()
-        myalphabet.set_alphabet(alphabet)
+        myalphabet.set_alphabet(args.alphabet)
 
         myalphabet.compile_module(args)
         list_patterns = myalphabet.prepare_random_patterns(0, args.max_string_length, 1)
@@ -376,7 +376,7 @@ def main():
             )
 
         myalphabet = Alphabet()
-        myalphabet.set_alphabet(alphabet, verbose=False)
+        myalphabet.set_alphabet(args.alphabet, verbose=False)
 
         myalphabet.compile_module(args)
         myalphabet.check_string_is_in_alphabet(args.distance[0])