cdm/src/main/java/ucar/nc2/ft/point/standard/Evaluator.java
static public Structure findNestedStructure(Structure s) {
    for (Variable v : s.getVariables()) {
      if ((v instanceof Structure))
        return (Structure) v;
    }
    return null;
  }
static public Structure findNestedStructure(Structure s) {
    for (Variable v : s.getVariables()) {
      if ((v instanceof Structure))
        return (Structure) v;
    }
    return null;
  }
Find first nested structure
@param s in this structure
@return first nested structure or null