Adding and removing collide masks (Python, Panda3D)

gistfile1.py

def addCollideMask(np,mask):
    """Add mask to the NodePath's existing collide mask (do a binary OR of
    the two bitmasks)."""
    np.setCollideMask(np.getCollideMask() | mask)
 
def removeCollideMask(np,mask):
    """Remove mask from the NodePath's existing collide mask (all bits set
to 1 in mask will be set to 0 in the NodePath's mask)."""
    # Need to copy mask first to avoid modifying it in place.
    copy = mask & BitMask32.allOn()
    copy.invertInPlace()
    np.setCollideMask(np.getCollideMask() & copy)