Remove whitespace around parameter '=' sign.

def fix_e251(self, result):
        """Remove whitespace around parameter '=' sign."""
        line_index = result['line'] - 1
        target = self.source[line_index]

        # This is necessary since pycodestyle sometimes reports columns that
        # goes past the end of the physical line. This happens in cases like,
        # foo(bar\n=None)
        c = min(result['column'] - 1,
                len(target) - 1)

        if target[c].strip():
            fixed = target
        else:
            fixed = target[:c].rstrip() + target[c:].lstrip()

        # There could be an escaped newline
        #
        #     def foo(a=\
        #             1)
        if fixed.endswith(('=\\\n', '=\\\r\n', '=\\\r')):
            self.source[line_index] = fixed.rstrip('\n\r \t\\')
            self.source[line_index + 1] = self.source[line_index + 1].lstrip()
            return [line_index + 1, line_index + 2]  # Line indexed at 1

        self.source[result['line'] - 1] = fixed