add envvar option to skip prompt

multiagent/__init__.py

@@ -1,3 +1,4 @@
+import os
 import warnings
 
 from gym.envs.registration import register
@@ -26,4 +27,6 @@
               "support for installation via pip, and numerous other large quality of life improvements. \nWe "
               "encourage researchers to switch to this maintained version for all purposes other than comparing "
               "to results run on this version of the environments. \n")
-input("Please read the raised warning, then press Enter to continue...\n")
+
+if os.getenv('SUPPRESS_MA_PROMPT') != '1':
+    input("Please read the raised warning, then press Enter to continue... (to suppress this prompt, please set the environment variable `SUPPRESS_MA_PROMPT=1`)\n")