Is the stripping of whitespace necessary for this fix?

Currently, the complex constructor accepts whitespace both inside and outside the (optional) parentheses:

>>> complex(' ( 2+3j ) ')
(2+3j)

The classes of whitespace accepted in each position are the same.  IIUC, with your patch, that consistency would be lost---is that right?

If the whitespace stripping isn't necessary then I'd prefer to leave that change for another issue.