### Question:
Scope { public synchronized Scope<T> find_scope(String name) throws AmbiguousNameException { return find_scope(new HierarchicalName(false, name)); } Scope(String name); final String name(); final Scope<T> parent(); final HierarchicalName absolute_hname(); synchronized final void add(Scope<T> scope); synchronized final void add(T obj); synchronized T find(String name); synchronized Scope<T> find_scope(String name); synchronized T find(HierarchicalName hn); synchronized Scope<T> find_scope(HierarchicalName hn); synchronized Set<T> all(); synchronized final void link(Scope<T> scope); synchronized Set<T> all_recursive(); synchronized boolean child_scope_of(Scope<?> scope); static Scope<?> common_inner_most_parent_scope(
			Set<? extends Scope<?>> scopes);  }### Answer:
@Test(expected = AssertionError.class) public void finding_scope_with_null_string() throws Exception { TestScope s = new TestScope(); s.find_scope((String) null); }
@Test(expected = AssertionError.class) public void finding_scope_with_null_hierarchical_name() throws Exception { TestScope s = new TestScope(); s.find_scope((HierarchicalName) null); }