@Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    BoundSignature that = (BoundSignature) o;
    return Objects.equals(functionName, that.functionName)
        && Objects.equals(returnType, that.returnType)
        && Objects.equals(argumentTypes, that.argumentTypes);
  }
The absolute canonical name of the function.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/function/BoundSignature.java