str.find(sub[, start[, end]])
Return the lowest index in the string where substring sub is found within the slice s[start:end]. Optional arguments start and end are interpreted as in slice notation. Return -1 if sub is not found.
Note The find() method should be used only if you need to know the position of sub. To check if sub is a substring or not, use the in operator: >>> 'Py' in 'Python'
True