Inconsistency in indent function on xml.etree.ElementTree

Question

the aim of the code is to insert XML chunks into an XML base structure to create the final XML output.

import xml.etree.ElementTree as ET
from xml.etree.ElementTree import XMLParser

base_tree     = ET.parse('base_structure_01.XML')
base_root     = base_tree.getroot()

specification = base_tree.find('specification')
applicability = specification.find('applicability')

entity_tree   = ET.parse('entity_structure_01.XML')
entity_root   = entity_tree.getroot()

ET.indent(entity_root,space ="    ",level=3)

applicability.append(entity_root)
base_tree.write('output.xml')

Content of base_structure_01.XML :

<ids>
    <specification>
        <applicability>
        </applicability>
        <requirements>
        </requirements>
    </specification>
</ids>  

Content of entity_structure_01.XML :

<entity>  
    <name>
        <simpleValue>name</simpleValue>
    </name>
    <predefinedtype>
        <simpleValue>predefinedtype</simpleValue>
    </predefinedtype>
</entity>

What I would like to be the output :

<ids>
    <specification>
        <applicability>
            <entity>
                <name>
                    <simpleValue>name</simpleValue>
                </name>
                <predefinedtype>
                    <simpleValue>predefinedtype</simpleValue>
                </predefinedtype>
            </entity>
        </applicability>
        <requirements>
        </requirements>
    </specification>
</ids>

What is currently the output :

<ids>
    <specification>
        <applicability>
        <entity>
                <name>
                    <simpleValue>name</simpleValue>
                </name>
                <predefinedtype>
                    <simpleValue>predefinedtype</simpleValue>
                </predefinedtype>
            </entity></applicability>
        <requirements>
        </requirements>
    </specification>
</ids>

problems :

• 1st <entity> is not correctly indented
• The end </entity> is on the same line as </applicability>

I know there are other options to indent text, I just wanted to know if with the xml.etree.ElementTree it was possible to solve this easily.

Thank you for your time

Answer 1

It works if you apply indent() on the whole tree, after append().

Replace

ET.indent(entity_root,space ="    ",level=3)

applicability.append(entity_root)

with this:

applicability.append(entity_root)

ET.indent(base_root,space ="    ")