prompt-toolkit has been updated many times since slcli-shell was created. p_shortcuts.prompt() passed arguments that are long deprecated causing the shell to fail.

Author: ScottieD

SoftLayer/shell/core.py

@@ -69,15 +69,14 @@ def get_prompt_tokens(_):
                 tokens.append((token.Token.Prompt, '> '))
 
             return tokens
-
         try:
             line = p_shortcuts.prompt(
                 completer=complete,
-                history=history,
+                complete_while_typing=True,
                 auto_suggest=p_auto_suggest.AutoSuggestFromHistory(),
-                get_prompt_tokens=get_prompt_tokens,
             )
 
+
             # Parse arguments
             try:
                 args = shlex.split(line)