<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def start_output (self):
 """Write start of checking info as DOT comment."""

        super(DOTLogger, self).start_output()
        if self.has_part("intro"):
            self.write_intro()
            self.writeln()
        self.writeln(u"digraph G {")
        self.writeln(u"  graph [")
        self.writeln(u"    charset=\"%s\"," % self.get_charset_encoding())
        self.writeln(u"  ];")
        self.flush()