ENH: use getroottree to determine tree for getting the paths

src/caoscrawler/structure_elements.py

@@ -175,11 +175,9 @@ class XMLTagElement(StructureElement):
     Stores elements of an XML tree.
     """
 
-    def __init__(self, element: lxml.etree.Element,
-                 tree: lxml.etree.ElementTree):
-        super().__init__(tree.getelementpath(element))
+    def __init__(self, element: lxml.etree.Element):
+        super().__init__(element.getroottree().getelementpath(element))
         self.tag = element
-        self.tree = tree
 
 
 class XMLTextNode(StructureElement):
@@ -187,8 +185,7 @@ class XMLTextNode(StructureElement):
     Stores text nodes of XML trees.
     """
 
-    def __init__(self, element: lxml.etree.Element,
-                 tree: lxml.etree.ElementTree):
+    def __init__(self, element: lxml.etree.Element):
         """
         Initializes this XML text node.
 
@@ -199,7 +196,7 @@ class XMLTextNode(StructureElement):
         - XMLTextNodes just have a text and the name is just for identifying the structure element.
           They can only be matched using the match entry in the XMLTextNodeConverter.
         """
-        super().__init__(tree.getelementpath(element))
+        super().__init__(element.getroottree().getelementpath(element))
         self.tag = element
         self.value = element.text
 
@@ -219,7 +216,8 @@ class XMLAttributeNode(StructureElement):
         key: The key which identifies the attribute in the list of attributes.
         tree: The tree containing the element which is used to set the node path.
         """
-        super().__init__(tree.getelementpath(element))
+        super().__init__(element.getroottree().getelementpath(element))
         self.value = element.attrib[key]
         self.key = key
+        # TODO: use getpath instead of getlementpath?
         self.tag = element