While such points could be represented by Python tuples, this special object type requires less memory and overloads some arithmetic operators.
Point objects are immutable.
If called with one argument, the argument must be a sequence of two numbers. If r is omitted, it defaults to 1.0. Return a unit vector pointing in the same direction. If the point's length is 0, raise a ZeroDivisionError. If r is 0, so is phi .