Same as `write`, but adds success coloring if enabled.

            `buf`
                Data buffer to write.
            `newline`
                Append newline character to buffer before writing.

def success(self, buf, newline=True):
        """ Same as `write`, but adds success coloring if enabled.

            `buf`
                Data buffer to write.
            `newline`
                Append newline character to buffer before writing.
            """

        if self._colored:
            buf = self.ESCAPE_GREEN + buf + self.ESCAPE_CLEAR

        self.write(buf, newline)