getChild method
The child called name with multiplicity, if any. name may be
* to address children by position.
Implementation
TreeElement? getChild(String name, int multiplicity) =>
_children.find(name, multiplicity);
The child called name with multiplicity, if any. name may be
* to address children by position.
TreeElement? getChild(String name, int multiplicity) =>
_children.find(name, multiplicity);