Just send xml bytes directly:

#!/usr/bin/env python2
# -*- coding: utf-8 -*-
import requests

xml = """<?xml version='1.0' encoding='utf-8'?>
<a>б</a>"""
headers = {'Content-Type': 'application/xml'} # set what your server accepts
print requests.post('http://httpbin.org/post', data=xml, headers=headers).text

Output

{
  "origin": "x.x.x.x",
  "files": {},
  "form": {},
  "url": "http://httpbin.org/post",
  "args": {},
  "headers": {
    "Content-Length": "48",
    "Accept-Encoding": "identity, deflate, compress, gzip",
    "Connection": "keep-alive",
    "Accept": "*/*",
    "User-Agent": "python-requests/0.13.9 CPython/2.7.3 Linux/3.2.0-30-generic",
    "Host": "httpbin.org",
    "Content-Type": "application/xml"
  },
  "json": null,
  "data": "<?xml version='1.0' encoding='utf-8'?>\n<a>\u0431</a>"
}

You want to give the XML data from a file to requests.post. But, this function will not open a file for you. It expects you to pass a file object to it, not a file name. You need to open the file before you call requests.post.

Try this:

import requests

# Set the name of the XML file.
xml_file = "xxx.xml"

headers = {'Content-Type':'text/xml'}

# Open the XML file.
with open(xml_file) as xml:
    # Give the object representing the XML file to requests.post.
    r = requests.post('https://example.com/serverxml.asp', data=xml, headers=headers)

print (r.content);

Once, when I had to do a similar thing, I did like this:

requests.post(url, data=xml_string, headers={'Content-Type':'application/xml; charset=UTF-8'})

It's common to return a 200 response even when a 201 response would strictly be more appropriate. Are you sure that the request isn't correctly processed even if you are getting a 'correct' response?

you should try like this

def frame_xml(AddressVerified,AmountPaid):
    xml_data = """<?xml version="1.0" encoding="utf-8" standalone="yes"?>
    <entry xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices"  xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/ metadata" xmlns="http://www.w3.org/2005/Atom">
    <category scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme" term="SS.WebData.Order" />
     <title />
     <author>
     <name />
     </author>
     <id />
     <content type="application/xml">
     <m:properties>
       <d:AddressVerified m:type="Edm.Byte">%s</d:AddressVerified>
       <d:AmountPaid m:type="Edm.Decimal">%s</d:AmountPaid>
     </m:properties>
    </content>
   </entry>"""%(AddressVerified,AmountPaid)
   return xml_data

headers = {'Content-Type': 'application/xml'}
xml_data = frame_xml('AddressVerified','AmountPaid')
print requests.post('https://data.shipstation.com/1.2/Orders', data=xml_data, headers=headers).text

I think this might help you, my friend!

    import requests

    request = '''
    <?xml version="1.0" encoding="UTF-8"?>
    <Requ>
    <GivenName>Özdemam</GivenName>
    <FamilyNameGrünzl</FamilyName>
    </Requ>
    '''.encode('utf-8')
    headers = {'Content-Type': 'text/xml': 'charset=utf-8'}
    req = requests.Request('POST', 'http://192.168.1.5:8888/api',
                   headers=headers,
                   data=request)

    prepped_requ = req.prepare()
    s = requests.Session()
    http_response = s.send(prepped_requ)
    print http_response