"ab".remove_prefix("c")

# output:
stdin:1:20
  ╷
1 │ "ab".remove_prefix("c")
  ╵                    ^~~
Error: Cannot remove this prefix. "ab" does not start with "c".

stdin:1:19
  ╷
1 │ "ab".remove_prefix("c")
  ╵                   ^
In call to method 'String.remove_prefix'.