import difflib

str1 = "I understand how customers do their choice. Difference"
str2 = "I understand how customers do their choice."

seq = difflib.SequenceMatcher(None, str1, str2)

d = seq.ratio()*100

d

88.65979381443299

def get_similarity(str1, str2):
    seq = difflib.SequenceMatcher(None, str1, str2)
    d = seq.ratio()*100
    return d

get_similarity(str1, str2)

88.65979381443299

get_similarity("Toronto is nice", "Toronto is looking nice")

78.94736842105263