How to parse kml file as tree structure in python?

I have a kml file that I am trying to parse in python,what I wanted is to pass val3 from SimpleData as an argument,and the coordinates for only that placemark tag will be retrieved,I have worked on xpath before: A typical example in xpath expression would be:

value = '..'
for val in (//Placement/ExtendedData/SimpleData[contains(text(), "+value+")]):
    print val.find_element_by_xpath(//coordinates)

However I can't seem to get the same by using element tree in Python:

This is the kml file
:

<?xml version="1.0" encoding="utf-8" ?>
<kml xmlns="http://www.opengis.net/kml/2.2">
<Document id="root_doc">
<Schema name="" id="">
    <SimpleField name="NAME_0" type="string"></SimpleField>
    <SimpleField name="NAME_1" type="string"></SimpleField>
</Schema>
<Folder><name></name>
  <Placemark>
    <Style><LineStyle><color>ff0000ff</color></LineStyle><PolyStyle><fill>0</fill></PolyStyle></Style>
    <ExtendedData><SchemaData schemaUrl="#gadm36_IND_3">
        <SimpleData name="NAME_0">val1</SimpleData>
        <SimpleData name="NAME_1">val2</SimpleData>
        <SimpleData name="NAME_2">val3</SimpleData>
    </SchemaData></ExtendedData>
      <MultiGeometry><Polygon><outerBoundaryIs><LinearRing><coordinates>92.7877807617189,9.24416637420654 92.7888870239258,9.24305438995361 92.7897186279296,9.24306106567383 92.7902832031251,9.24250030517589 92.7905578613282,9.24250030517589 92.7911148071289,9.24194431304943 92.7913894653321,9.24194431304943 92.7922210693359,9.24110984802257 92.7922210693359,9.24083423614508 92.7930526733399,9.23999977111822
      </coordinates></LinearRing>...
      <Placemark>
    <Style><LineStyle><color>ff0000ff</color></LineStyle><PolyStyle><fill>0</fill></PolyStyle></Style>
    <ExtendedData><SchemaData schemaUrl="#gadm36_IND_3">
        <SimpleData name="NAME_0">val1</SimpleData>
        <SimpleData name="NAME_1">val2</SimpleData>
        <SimpleData name="NAME_2">val3</SimpleData>
    </SchemaData></ExtendedData>
      <MultiGeometry><Polygon><outerBoundaryIs><LinearRing><coordinates>92.7877807617189,9.24416637420654 92.7888870239258,9.24305438995361 92.7897186279296,9.24306106567383 92.7902832031251,9.24250030517589 92.7905578613282,9.24250030517589 92.7911148071289,9.24194431304943 92.7913894653321,9.24194431304943 92.7922210693359,9.24110984802257 92.7922210693359,9.24083423614508 92.7930526733399,9.23999977111822
      </coordinates></LinearRing>...

This is what Im stuck on:

import xml.etree.ElementTree as ET
tree = ET.parse('')
root = tree.getroot()
for val in root.findall('.//{http://www.opengis.net/kml/2.2}SimpleData[@text=""]//coordinates'):
    print val.text

Solution

Use lxml with XPath and namespaces. In the XPath selector you can navigate from the SimpleData with text val3 back to the Placemark ancestor and from there to the coordinates.

from lxml import etree

tree = etree.parse("so.xml")
nsmap = {"kml": "http://www.opengis.net/kml/2.2"}

listOfCoordinates = tree.xpath("//kml:SimpleData[text()=\"val3\"]/ancestor::kml:Placemark//kml:coordinates", namespaces=nsmap)
print(listOfCoordinates[0].text)

Output:

92.7877807617189,9.24416637420654 92.7888870239258,9.24305438995361 92.7897186279296,9.24306106567383 92.7902832031251,9.24250030517589 92.7905578613282,9.24250030517589 92.7911148071289,9.24194431304943 92.79138
94653321,9.24194431304943 92.7922210693359,9.24110984802257 92.7922210693359,9.24083423614508 92.7930526733399,9.23999977111822