Method argument conversion: 'tuple' has no attribute 'attribute'
<p>I have a simple vector class that overloards several arithmetic operators:</p>

<pre><code>class vec2:
    x = 0.0
    y = 0.0

    def __add__(self,other):
        self.x = other.x
        self.y = other.y

    def __mul__(self,scalar):
        self.x *= scalar
        self.y *= scalar
</code></pre>

<p>However, somewhere else I call the method like this:</p>

<pre><code>class foo:
    position = vec2()
    velocity = vec2()

    def update(self,dt):
        self.position += self.velocity * dt;
</code></pre>

<p>However, once I get to the update function, the interpreter gives an error: </p>

<pre><code>'tuple' object has no attribute 'x'
</code></pre>

<p>inside the <code>__add__</code> function.</p>

<p>Why is "other" in <code>__add__</code> passed as a tuple, and not a vec2?</p>

<p>The entire code is <a href="http://pastebin.com/rtar2dKg" rel="nofollow">here</a>.</p>
