sum of digits in a string

sumOfDigits.py

def sumOfDigits(str):
    temp = ''
    sum = 0

    for i in range(len(str)):
        if str[i].isdigit():
            temp += str[i]
        else:
            if temp.isdigit():
                sum += int(temp)
                temp = ''

    if temp.isdigit():
        sum += int(temp)
    return sum

#TEST
str = '123adgg2sds3'
print(sumOfDigits(str))