Is there a built-in Python vector class?

import mathclass Vector:    'Represents a 2D vector.'    def __init__(self, x = 0, y = 0):        self.x = float(x)        self.y = float(y)            def __add__(self, val):        return Point( self[0] + val[0], self[1] + val[1] )        def __sub__(self,val):        return Point( self[0] - val[0], self[1] - val[1] )        def __iadd__(self, val):        self.x = val[0] + self.x        self.y = val[1] + self.y        return self            def __isub__(self, val):        self.x = self.x - val[0]        self.y = self.y - val[1]        return self        def __div__(self, val):        return Point( self[0] / val, self[1] / val )        def __mul__(self, val):        return Point( self[0] * val, self[1] * val )        def __idiv__(self, val):        self[0] = self[0] / val        self[1] = self[1] / val        return self            def __imul__(self, val):        self[0] = self[0] * val        self[1] = self[1] * val        return self                    def __getitem__(self, key):        if( key == 0):            return self.x        elif( key == 1):            return self.y        else:            raise Exception("Invalid key to Point")            def __setitem__(self, key, value):        if( key == 0):            self.x = value        elif( key == 1):            self.y = value        else:            raise Exception("Invalid key to Point")            def __str__(self):        return "(" + str(self.x) + "," + str(self.y) + ")"Point = Vector        def DistanceSqrd( point1, point2 ):    'Returns the distance between two points squared. Marginally faster than Distance()'    return ( (point1[0]-point2[0])**2 + (point1[1]-point2[1])**2)def Distance( point1, point2 ):    'Returns the distance between two points'    return math.sqrt( DistanceSqrd(point1,point2) )def LengthSqrd( vec ):    'Returns the length of a vector sqaured. Faster than Length(), but only marginally'    return vec[0]**2 + vec[1]**2def Length( vec ):    'Returns the length of a vector'    return math.sqrt( LengthSqrd(vec) )def Normalize( vec ):    'Returns a new vector that has the same direction as vec, but has a length of one.'    if( vec[0] == 0. and vec[1] == 0. ):        return Vector(0.,0.)    return vec / Length(vec)def Dot( a,b ):    'Computes the dot product of a and b'    return a[0]*b[0] + a[1]*b[1]def ProjectOnto( w,v ):    'Projects w onto v.'    return v * Dot(w,v) / LengthSqrd(v)