[lxml] XPath nie działa tak jak bym tego chciał

Witam, mam część pliku xml (poniżej). I na jego podstawie chciałbym napisać XPath aby wyszukiwał atrybutu "ReferenceType="HasNotifier"".
Jeśli go znajdzie to aby wyświetlił "OBJECTS.WAAA05.01.002CC-ESSO01.Pressed".

Czyli w tym konkretnym przapadku ma znależć w 105 linijce "HasNotifier" i wypluć z linijki nr 99 "OBJECTS.WAAA05.01.002CC-ESSO01.Pressed"

Napisałem coś takiego

 //Reference[@ReferenceType="HasNotifier"]/../../../UAVariable/@NodeId

ale niestety nie działa tak jak bym tego chciał. Jestem początkującym dlatego proszę o wyrozumiałość i pomoc :)
Na tej stronie testuje xpath - > http://codebeautify.org/Xpath-Tester

<?xml version="1.0" encoding="UTF-8" ?>
<!-- created at 2017-03-09 08:23:40 -->
<UANodeSet xmlns="http://foundation.org/UA/2011/03/NodeSet.xsd" xmlns:uax="http://foundation.org/UA/2008/02/Types.xsd">
	<NamespaceUris>
		<Uri>http://www.vise.com/Server/UA/</Uri>
	</NamespaceUris>
	<Aliases>
		<!-- data types -->
		<Alias Alias="Boolean">i=1</Alias>
		<Alias Alias="SByte">i=2</Alias>
		<Alias Alias="Byte">i=3</Alias>
		<Alias Alias="Int16">i=4</Alias>
		<Alias Alias="UInt16">i=5</Alias>
		<Alias Alias="Int32">i=6</Alias>
		<Alias Alias="UInt32">i=7</Alias>
		<Alias Alias="Int64">i=8</Alias>
		<Alias Alias="UInt64">i=9</Alias>
		<Alias Alias="Float">i=10</Alias>
		<Alias Alias="Double">i=11</Alias>
		<Alias Alias="String">i=12</Alias>
		<Alias Alias="DateTime">i=13</Alias>
		<Alias Alias="ByteString">i=15</Alias>
		<Alias Alias="XmlElement">i=16</Alias>
		<Alias Alias="NodeId">i=17</Alias>
		<Alias Alias="LocalizedText">i=21</Alias>
		<!-- references -->
		<Alias Alias="Organizes">i=35</Alias>
		<Alias Alias="HasEventSource">i=36</Alias>
		<Alias Alias="HasModellingRule">i=37</Alias>
		<Alias Alias="HasTypeDefinition">i=40</Alias>
		<Alias Alias="HasSubtype">i=45</Alias>
		<Alias Alias="HasProperty">i=46</Alias>
		<Alias Alias="HasComponent">i=47</Alias>
		<Alias Alias="HasNotifier">i=48</Alias>
		<!-- types -->
		<Alias Alias="BaseDataType">i=24</Alias>
		<Alias Alias="BaseObjectType">i=58</Alias>
		<Alias Alias="FolderType">i=61</Alias>
		<Alias Alias="BaseVariableType">i=62</Alias>
		<Alias Alias="PropertyType">i=68</Alias>
		<!-- modelling rules -->
		<Alias Alias="New">i=78</Alias>
		<Alias Alias="Shared">i=79</Alias>
	</Aliases>
	<UAObject NodeId="ns=1;s=AGENT" BrowseName="1:AGENT">
		<DisplayName Locale="en">AGENT</DisplayName>
		<Description Locale="en">AGENT</Description>
		<References>
			<Reference ReferenceType="HasComponent" IsForward="false">i=85</Reference>
			<Reference ReferenceType="HasTypeDefinition">ns=1;s=ObjectTypes.VISE.Server.Local</Reference>
		</References>
		<Extensions>
			<VISE ExportedNodeId="ns=1;s=AGENT.OBJECTS.WAAA05.01.002CC-ESSO01" ExportedBrowseName="1:002CC-ESSO01" Upstream="true"/>
		</Extensions>
	</UAObject>
	<UAObject NodeId="ns=1;s=AGENT.OBJECTS" BrowseName="1:OBJECTS">
		<DisplayName Locale="en">OBJECTS</DisplayName>
		<Description Locale="en">OBJECTS</Description>
		<References>
			<Reference ReferenceType="HasComponent" IsForward="false">ns=1;s=AGENT</Reference>
			<Reference ReferenceType="HasTypeDefinition">FolderType</Reference>
		</References>
		<Extensions>
			<VISE Upstream="true"/>
		</Extensions>
	</UAObject>
	<UAObject NodeId="ns=1;s=AGENT.OBJECTS.WAAA05" BrowseName="1:WAAA05">
		<DisplayName Locale="en">WAAA05</DisplayName>
		<Description Locale="en">WAAA05</Description>
		<References>
			<Reference ReferenceType="HasComponent" IsForward="false">ns=1;s=AGENT.OBJECTS</Reference>
			<Reference ReferenceType="HasTypeDefinition">FolderType</Reference>
		</References>
		<Extensions>
			<VISE Upstream="true"/>
		</Extensions>
	</UAObject>
	<UAObject NodeId="ns=1;s=AGENT.OBJECTS.WAAA05.01" BrowseName="1:01">
		<DisplayName Locale="en">01</DisplayName>
		<Description Locale="en">01</Description>
		<References>
			<Reference ReferenceType="HasComponent" IsForward="false">ns=1;s=AGENT.OBJECTS.WAAA05</Reference>
			<Reference ReferenceType="HasTypeDefinition">FolderType</Reference>
		</References>
		<Extensions>
			<VISE Upstream="true"/>
		</Extensions>
	</UAObject>
	<UAObject NodeId="ns=1;s=AGENT.OBJECTS.WAAA05.01.002CC-ESSO01" BrowseName="1:002CC-ESSO01">
		<DisplayName Locale="en">002CC-ESSO01</DisplayName>
		<Description Locale="en">002CC-ESSO01</Description>
		<References>
			<Reference ReferenceType="HasComponent" IsForward="false">ns=1;s=AGENT.OBJECTS.WAAA05.01</Reference>
			<Reference ReferenceType="HasTypeDefinition">ns=1;s=ObjectTypes.PROJECT.Foren.Notek_Table</Reference>
			<Reference ReferenceType="HasComponent">ns=1;s=ObjectTypes.PROJECT.Foren.Notek_Table.Overview</Reference>
			<Reference ReferenceType="HasComponent">ns=1;s=ObjectTypes.PROJECT.Foren.Notek_Table.Version</Reference>
		</References>
	</UAObject>
	<UAVariable NodeId="ns=1;s=AGENT.OBJECTS.WAAA05.01.002CC-ESSO01.Pressed" BrowseName="1:Pressed" DataType="Boolean" AccessLevel="7" UserAccessLevel="7" Historizing="true">
		<DisplayName Locale="en">Pressed</DisplayName>
		<Description Locale="en">002CC-ESSO01.(WAAA05.01?1)</Description>
		<References>
			<Reference ReferenceType="HasComponent" IsForward="false">ns=1;s=AGENT.OBJECTS.WAAA05.01.002CC-ESSO01</Reference>
			<Reference ReferenceType="HasTypeDefinition">BaseVariableType</Reference>
			<Reference ReferenceType="HasNotifier">ns=1;s=ObjectTypes.PROJECT.Foren.Notek_Table.Pressed.ButtonPressed</Reference>
		</References>
		<Value>
			<uax:Boolean>false</uax:Boolean>
		</Value>
	</UAVariable>
	<UAVariable NodeId="ns=1;s=AGENT.OBJECTS.WAAA05.01.002CC-ESSO01.Pressed.MirrorInput" BrowseName="1:MirrorInput" DataType="String" AccessLevel="7" UserAccessLevel="7" Historizing="true">
		<DisplayName Locale="en">MirrorInput</DisplayName>
		<Description Locale="en">MirrorInput</Description>
		<References>
			<Reference ReferenceType="HasComponent" IsForward="false">ns=1;s=AGENT.OBJECTS.WAAA05.01.002CC-ESSO01.Pressed</Reference>
			<Reference ReferenceType="HasTypeDefinition">ns=1;s=VariableTypes.VISE.Mirror.Input</Reference>
		</References>
		<Value>
			<uax:String>Serwise/ns=4;s=Signals.WAAA05_01_002CC_ESSO01</uax:String>
		</Value>
	</UAVariable>
</UANodeSet>