def lp(v1, v2=None, p=2):
"""Find the L_p norm. If passed one vector, find the length of that vector.
If passed two vectors, find the length of the difference between them.
def lp(v1, v2=None, p=2):
"""Find the L_p norm. If passed one vector, find the length of that vector.
If passed two vectors, find the length of the difference between them.