Make it return empty collection when no parent

lib/jira/base.rb

@@ -475,17 +475,7 @@ def maybe_nested_attribute(attribute_name, nested_under = nil)
     end
 
     def self.maybe_nested_attribute(attributes, attribute_name, nested_under = nil)
-      return attributes[attribute_name] if nested_under.nil?
-      if nested_under.instance_of? Array
-        final = nested_under.inject(attributes) do |parent, key|
-          break if parent.nil?
-          parent[key]
-        end
-        return nil if final.nil?
-        final[attribute_name]
-      else
-        return attributes[nested_under][attribute_name]
-      end
+      return attributes.dig(*[*nested_under, attribute_name])
     end
 
     def url_with_query_params(url, query_params)

spec/jira/base_spec.rb

@@ -494,6 +494,11 @@ class JIRA::Resource::HasManyExample < JIRA::Base # :nodoc:
       end
     end
 
+    it 'returns an empty collection for empty nested has_many relationships' do
+      subject = JIRA::Resource::HasManyExample.new(client)
+      expect(subject.brunchmuffins.length).to eq(0)
+    end
+
     it 'allows it to be deeply nested' do
       subject = JIRA::Resource::HasManyExample.new(client, attrs: { 'nested' => {
                                                      'breakfastscone' => { 'breakfastscones' => [{ 'id' => '123' }, { 'id' => '456' }] }