looks like the check on your system has some coding issues 
If you have a look at the actual version on github you can see in line 115 the key word Optional, this is missing in your check.
def cluster_check_cisco_wlc(
item: str,
params: Mapping[str, Any],
section: Mapping[str, Optional[Section]],
) -> CheckResult:
if you add this to your check, you also need to adjust the import statement in line 36
from typing import Any, Dict, List, Mapping, Optional