verb_past.py

IRREGULAR_HASH = {"stop": "stopped", "go": "gone", "read": "read"}
VOWELS = ["a", "i", "u", "e", "o"]


def verb_past(str):
    if IRREGULAR_HASH.get(str):
        return IRREGULAR_HASH[str]
    elif str[-1] == "y" and not str[-2] in VOWELS:
        return str[:-1] + "ied"
    elif str[-1] == "c":
        return str + "ked"
    elif str[-1] == "c":
        return str + "ked"
    elif str[-1] == "e":
        return str + "d"
    return str + "ed"


print(verb_past("play"))
print(verb_past("like"))
print(verb_past("try"))
print(verb_past("stop"))
print(verb_past("heat"))
print(verb_past("picnic"))
print(verb_past("go"))
print(verb_past("read"))