FileOpen

POST /DocsVision/StorageServer/StorageServerService.asmx HTTP/1.1
Host: DOCSVISION_SERVER.COM
Content-Type: text/xml; charset=utf-8
Content-Length: length
SOAPAction: "http://schemas.docsvision.com/Platform/2009-02-03/StorageServer/FileOpen"

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <FileOpen xmlns="http://schemas.docsvision.com/Platform/2009-02-03/StorageServer/">
      <sessionId>guid</sessionId>
      <fileId>guid</fileId>
      <modify>boolean</modify>
    </FileOpen>
  </soap:Body>
</soap:Envelope>

HTTP/1.1 200 OK
Content-Type: text/xml; charset=utf-8
Content-Length: length

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <FileOpenResponse xmlns="http://schemas.docsvision.com/Platform/2009-02-03/StorageServer/">
      <fileHandleId>guid</fileHandleId>
    </FileOpenResponse>
  </soap:Body>
</soap:Envelope>

session.headers['SOAPAction'] = "http://schemas.docsvision.com/Platform/2009-02-03/StorageServer/FileOpen" (1)

body = """<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <FileOpen xmlns="http://schemas.docsvision.com/Platform/2009-02-03/StorageServer/">
      <sessionId>6565c75b-298d-e511-9417-90e6ba57b9f8</sessionId>
      <fileId>2D6F7690-6B81-E511-9417-90E6BA57B9F8</fileId>
      <modify>false</modify>
    </FileOpen>
  </soap:Body>
</soap:Envelope>""" (2)

response = session.post(url, data=body) (3)

responseParsed = ElementTree.fromstring(response.content)
print(responseParsed.findtext(".//{http://schemas.docsvision.com/Platform/2009-02-03/StorageServer/}fileHandleId")) (4)