lxml not adding newlines when inserting a new element into existing xml

I have a large set of existing xml files, and I am trying to add one element to all of them (they are pom.xml for a number of maven projects, and I am trying to add a parent element to all of them). The following is my exact code. The problem is that the final xml output in pom2.xml has the complete `parent` element in a single line. Though, when I print the element by itself, it writes it out in 4 lines as usual. How do I print out the complete xml with proper formatting for the `parent` element? ``` from lxml import etree parentPom = etree.Element('parent') groupId = etree.Element('groupId') groupId.text = 'org.myorg' parentPom.append(groupId) artifactId = etree.Element('artifactId') artifactId.text = 'myorg-master-pom' parentPom.append(artifactId) version = etree.Element('version') version.text = '1.0.0' parentPom.append(version) print etree.tostring(parentPom, pretty_print=True) pom = etree.parse("pom.xml") projectElement = pom.getroot() projectElement.insert(0, parentPom) file = open("pom2.xml", 'wb') file.write(etree.tostring(projectElement, pretty_print=True)) file.close() ``` Output of print: ``` <parent> <groupId>org.myorg</groupId> <artifactId>myorg-master-pom</artifactId> <version>1.0.0</version> </parent> ``` Output of same element in pom2.xml: ``` <parent><groupId>com.inmobi</groupId><artifactId>inmobi-master-pom</artifactId><version>1.0.1</version></parent><modelVersion>4.0.0</modelVersion> ```