disagree.py

def transform(last):
    """Transforms the last sentence of disagreement into the next"""
    # Strip the "I disagree with..." part from the setence, so that
    # we can work with just chains of "[your|my] disagreement of..."
    next = last[len("I disagree with "):]

    # Rotate your <-> my 
    next = next.replace("your", "p_my")
    next = next.replace("my", "p_your")
    next = next.replace("p_my", "my")
    next = next.replace("p_your", "your")

    # Prepend the "I disagree with..." and add one more term of disagreement
    next = "I disagree with your disagreement of " + next

    return next

def term(n):
    """Get the nth sentence of disagreement, where n is incremented for both speakers turns"""
    # Opening part
    s = "I disagree with your disagreement "

    for i in range(n):
        # Alternate between "my" and "your"
        s += "of your disagreement " if i % 2 == 1 else "of my disagreement "

    return s