Fix missing whitespace around operator.

def fix_e225(self, result):
        """Fix missing whitespace around operator."""
        target = self.source[result['line'] - 1]
        offset = result['column'] - 1
        fixed = target[:offset] + ' ' + target[offset:]

        # Only proceed if non-whitespace characters match.
        # And make sure we don't break the indentation.
        if (
            fixed.replace(' ', '') == target.replace(' ', '') and
            _get_indentation(fixed) == _get_indentation(target)
        ):
            self.source[result['line'] - 1] = fixed
            error_code = result.get('id', 0)
            try:
                ts = generate_tokens(fixed)
            except (SyntaxError, tokenize.TokenError):
                return
            if not check_syntax(fixed.lstrip()):
                return
            errors = list(
                pycodestyle.missing_whitespace_around_operator(fixed, ts))
            for e in reversed(errors):
                if error_code != e[1].split()[0]:
                    continue
                offset = e[0][1]
                fixed = fixed[:offset] + ' ' + fixed[offset:]
            self.source[result['line'] - 1] = fixed
        else:
            return []