update the --help option content to show the range of animal options an end user can select from

Author: HassanOHOsman

implement-cowsay/cow.py

@@ -2,20 +2,21 @@
 import sys
 import argparse
 
+listed_animals = [listed_animal for listed_animal in dir(cowsay) if callable(getattr(cowsay, listed_animal)) and not listed_animal.startswith("__") and listed_animal not in ["draw", "func", "get_output_string", "CowsayError"]]
+
 parser = argparse.ArgumentParser(
     prog="cow",
     description="Makes animals say things",
 )
 
-parser.add_argument("--animal", help="Select an animal to say anything")
+parser.add_argument("--animal", help="Select an animal to say anything", choices=listed_animals)
 parser.add_argument("message", nargs ="+", help="The message that the animal says")
 
 args = parser.parse_args()
 
 message = " ".join(args.message)
 animal = args.animal or "cow"
 
-listed_animals = [listed_animal for listed_animal in dir(cowsay) if callable(getattr(cowsay, listed_animal)) and not listed_animal.startswith("__") and listed_animal not in ["draw", "func", "get_output_string", "CowsayError"]]
 
 if animal not in listed_animals:
     print(f"Error: argument --animal: invalid choice: '{animal}'. Choose from: {', '.join(listed_animals)}")