anchor.diff:    String summary() {
       String markdown = '(';
       _labels.forEach((label) {
  -      markdown = markdown + label.label;
  -      if (label != _labels.last) markdown = markdown + ', ';
  +      markdown = '${markdown}${label.label}';
  +      if (label != _labels.last) markdown = '${markdown}, ';
       });
  -    markdown = markdown + ')';
  +    markdown = '${markdown})';
       return markdown;
     }
  +
  +  String toCsv() {
  +    String csv = '';
  +    labels.forEach((label) {
  +      csv += '${csv}${label.label}';
  +      if (label != labels.last) csv = '${csv},';
  +    });
  +    return csv;
  +  }
  +
     String toString() {
       return summary();
     }
  +
     Labels(this._labels);
     static Labels fromGraphQL(dynamic node) {
       var result = Labels(Set<Label>());
  
positive.code:   static Actor fromGraphQL(dynamic node) {
      return Actor(node['login'], node['url']);
    }
  
    @override
    bool operator==(Object other) =>
  
negative.code: 
    static var graphQLResponse = 
    '''
    {
      pageInfo ${PageInfo.graphQLResponse},
      nodes {
        __typename
        ... on CrossReferencedEvent {
          createdAt,
          source {
            __typename
            ...  on PullRequest {
              title,
              number,
            }
            ... on Issue {
              title,
              number,
            }
          }
        }
        ... on MilestonedEvent {
          createdAt,
          actor {
            login,
            resourcePath,
            url
          }, 
          id,
          milestoneTitle
        }
        ... on DemilestonedEvent {
          createdAt,          
          actor {
            login,
            resourcePath,
            url
          }, 
          id, 
          milestoneTitle
        }
        ... on AssignedEvent {
          createdAt,          
          assignee {
            ... on User {
              login,
              resourcePath,
              url
            }
            ... on Bot {
              login,
              resourcePath,
              url            
            }
          }
        }
        ... on UnassignedEvent {
          createdAt,          
          assignee {
            ... on User {
              login,
              resourcePath,
              url
            }
          }          
        }
      }
    }
    ''';
  
  }
  