Copies the shared library in self.so into the working directory for the wrapper
        module if it doesn't already exist.

def _copy_so(self, outpath):
        """Copies the shared library in self.so into the working directory for the wrapper
        module if it doesn't already exist.
        """
        from os import path
        if not path.isfile(outpath) and path.isfile(self.link):
            from shutil import copy
            copy(self.link, outpath)