code: func (g *Graph) GetDefinitionOk() (GraphDefinition, bool) {
  	if g == nil || g.Definition == nil {
  		return GraphDefinition{}, false
  	}
  	return *g.Definition, true
  }
docs: // GetDefinitionOk returns a tuple with the Definition field if it's non-nil, zero value otherwise
  // and a boolean to check if the value has been set.