cdm/src/main/java/ucar/nc2/Group.java
public boolean remove(Group g) {
    if (immutable) throw new IllegalStateException("Cant modify");
    return g != null && groups.remove(g);
  }
public boolean remove(Group g) {
    if (immutable) throw new IllegalStateException("Cant modify");
    return g != null && groups.remove(g);
  }
Remove an Attribute : uses the Group hashCode to find it.

@param g remove this Group.
@return true if was found and removed