# COPY ME INTO THE VISUALIZER

# Function Definitions
def last_name_first(s):
    """Returns: last name, first name"""
    first = first_name(s)
    last  = last_name(s)
    return last+', '+first

def first_name(s):
    """Returns: name before the space"""
    end = s.find(' ')
    return s[:end]

def last_name(s):
    """Returns: name after the space"""
    end = s.find(' ')
    return s[end+1:]

# Function Call (in Application Code)
name = last_name_first('Walker White')