code: def write(self, path, prog=None, format='raw'):
          
          if prog is None:
              prog = self.prog
  
          fobj, close = get_fobj(path, 'w+b')
          try:
              if format == 'raw':
                  data = self.to_string()
                  if isinstance(data, basestring):
                      if not isinstance(data, unicode):
                          try:
                              data = unicode(data, 'utf-8')
                          except Exception:
                              pass
  
                  try:
                      charset = self.get_charset()
                      if not PY3 or not charset:
                          charset = 'utf-8'
                      data = data.encode(charset)
                  except Exception:
                      if PY3:
                          data = data.encode('utf-8')
                      pass
  
                  fobj.write(data)
  
              else:
                  fobj.write(self.create(prog, format))
          finally:
              if close:
                  fobj.close()
  
          return True
docs: Write graph to file in selected format.
  
          Given a filename 'path' it will open/create and truncate
          such file and write on it a representation of the graph
          defined by the dot object and in the format specified by
          'format'. 'path' can also be an open file-like object, such as
          a StringIO instance.
  
          The format 'raw' is used to dump the string representation
          of the Dot object, without further processing.
          The output can be processed by any of graphviz tools, defined
          in 'prog', which defaults to 'dot'
          Returns True or False according to the success of the write
          operation.
  
          There's also the preferred possibility of using:
  
              write_'format'(path, prog='program')
  
          which are automatically defined for all the supported formats.
          [write_ps(), write_gif(), write_dia(), ...]