code: Artifact createArtifact(ArtifactFactory artifactFactory) {
      if (groupId == null || artifactId == null || version == null || type == null) {
        throw new NullPointerException("signaturesArtifact is missing some properties. Required are: groupId, artifactId, version, type");
      }
      return artifactFactory.createArtifactWithClassifier(groupId, artifactId, version, type, classifier);
    }
docs: Used by the mojo to fetch the artifact