code: public Optional<EdgeLabel> getOutEdgeLabel(String edgeLabelName) {
          EdgeLabel edgeLabel = getOutEdgeLabels().get(this.schema.getName() + "." + edgeLabelName);
          if (edgeLabel != null) {
              return Optional.of(edgeLabel);
          }
          return Optional.empty();
      }
docs: Out EdgeLabels are always in the same schema as the this VertexLabel' schema.
  So the edgeLabelName must not contain the schema prefix
  
  @param edgeLabelName
  @return