code: def to_dot(self, name='BDD'): # pragma: no cover
          
          parts = ['graph', name, '{']
          for node in self.dfs_postorder():
              if node is BDDNODEZERO:
                  parts += ['n' + str(id(node)), '[label=0,shape=box];']
              elif node is BDDNODEONE:
                  parts += ['n' + str(id(node)), '[label=1,shape=box];']
              else:
                  v = _VARS[node.root]
                  parts.append('n' + str(id(node)))
                  parts.append('[label="{}",shape=circle];'.format(v))
          for node in self.dfs_postorder():
              if node is not BDDNODEZERO and node is not BDDNODEONE:
                  parts += ['n' + str(id(node)), '--',
                            'n' + str(id(node.lo)),
                            '[label=0,style=dashed];']
                  parts += ['n' + str(id(node)), '--',
                            'n' + str(id(node.hi)),
                            '[label=1];']
          parts.append('}')
          return " ".join(parts)
docs: Convert to DOT language representation.
  
          See the
          `DOT language reference <http://www.graphviz.org/content/dot-language>`_
          for details.