Python - pseudo "Morse'a Code" - (Stackoverflow)

u = '1000111001'
u = '11011'

result = ""

while u:
    if u.startswith("000"):
        result += '333'
        u = u[3:]
    elif u.startswith("00"):
        result += '22'
        u = u[2:]
    elif u.startswith("0"):
        result += '1'
        u = u[1:]
    elif u.startswith("11"):
        result += '-'
        u = u[2:]
    elif u.startswith("1"):
        result += '.'
        u = u[1:]

print(result)