public java.lang.String getGroupName() {
        java.lang.Object ref = groupName_;
        if (!(ref instanceof java.lang.String)) {
          com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
          java.lang.String s = bs.toStringUtf8();
          groupName_ = s;
          return s;
        } else {
          return (java.lang.String) ref;
        }
      }
<pre>
Name of the group that the input belongs to. Features with the same group
name will be treated as one feature when computing attributions. Features
grouped together can have different shapes in value. If provided, there
will be one single attribution generated in
[Attribution.feature_attributions][google.cloud.aiplatform.v1.Attribution.feature_attributions],
keyed by the group name.
</pre>

<code>string group_name = 12;</code>

@return The groupName.
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/ExplanationMetadata.java