As @hurrial said, you can use translate-toolkit.
Install
This toolkit is only available using pip. To install it, run:
pip install translate-toolkit
Usage
Assume that you have the following simple sample.tmx file:
<tmx version="1.4">
  <header
    creationtool="XYZTool" creationtoolversion="1.01-023"
    datatype="PlainText" segtype="sentence"
    adminlang="en-us" srclang="en"
    o-tmf="ABCTransMem"/>
  <body>
    <tu>
      <tuv xml:lang="en">
        <seg>Hello world!</seg>
      </tuv>
      <tuv xml:lang="ar">
        <seg>اهلا بالعالم!</seg>
      </tuv>
    </tu>
  </body>
</tmx>
You can parse this simple file like so:
>>> from translate.storage.tmx import tmxfile
>>>
>>> with open("sample.tmx", 'rb') as fin:
...     tmx_file = tmxfile(fin, 'en', 'ar')
>>>
>>> for node in tmx_file.unit_iter():
...     print(node.source, node.target)
Hello world! اهلا بالعالم!
For more info, check the official documentation from here.