def area_tri(v1: 'mathutils.Vector', v2: 'mathutils.Vector', v3:
    'mathutils.Vector') ->float:
    """Returns the area size of the 2D or 3D triangle defined. 

    :param v1: Point1 
    :type v1: 'mathutils.Vector'
    :param v2: Point2 
    :type v2: 'mathutils.Vector'
    :param v3: Point3 
    :type v3: 'mathutils.Vector'
    """
    pass
