def __init__(self, *args):
        # no args gives identity matrix
        # 16 scalars collapsed from any combination of lists, tuples, vectors
        if not args:
            args = (1,0,0,0, 0,1,0,0, 0,0,1,0, 0,0,0,1)
        if len(args) == 4: args = collapse(*args)
        a = args[0]
        if isinstance(a, V):
            if len(a) != 16: raise TypeError, 'M() takes exactly 16 elements'
            self._v = list(a._v[:])
        elif isseq(a):
            if len(a) != 16: raise TypeError, 'M() takes exactly 16 elements'
            self._v = map(float, a)
        else:
            if len(args) != 16: raise TypeError, 'M() takes exactly 16 elements'
            self._v = map(float, args)
Constructs a new 4x4 matrix.
dataset/ETHPy150Open hhatto/autopep8/test/vectors_example.py/M.__init__