KeyDict.py

from typing import Dict, List, Tuple

def makeKeyDict(items:List[Tuple]) -> Dict:
    "Gives a list of tuples (a,b), returns a dict mapping a to set of b"
    d = {}
    for (a,b) in items:
        d[a] = set([b]).union(d.get(a,set()))
    return d
    
def findKeysWithMultipleValues(keydict) -> List:
    ks = []
    for (k,v) in keydict.items():
        if len(v) > 1:
            ks.append(k)
    return ks