request.xml

<soap-env:Envelope xmlns:soap-env="http://schemas.xmlsoap.org/soap/envelope/">
   <soap-env:Header>
      <ns0:User xmlns:ns0="http://www.b2breservas.com.br/b2bws/types/">xxx</ns0:User>
      <ns1:Password xmlns:ns1="http://www.b2breservas.com.br/b2bws/types/">xxx</ns1:Password>
   </soap-env:Header>
   <soap-env:Body>
      <ns0:OTA_PingRQ EchoToken="1234" Version="3.000" xmlns:ns0="http://www.opentravel.org/OTA/2003/05/alpha">
         <ns0:EchoData>1</ns0:EchoData>
      </ns0:OTA_PingRQ>
   </soap-env:Body>
</soap-env:Envelope>

sample.py

import zeep
import logging
from requests import Session


# You must initialize logging, otherwise you'll not see debug output.
logging.basicConfig()
logging.getLogger().setLevel(logging.DEBUG)
requests_log = logging.getLogger("requests.packages.urllib3")
requests_log.setLevel(logging.DEBUG)
requests_log.propagate = True

USERNAME = 'xxx'
PASSWORD = 'xxx'

session = Session()

wsdl = 'http://homolog.b2breservas.com.br:8080/b2bws-homolog-v2/OTAHotel?wsdl'
client = zeep.Client(wsdl=wsdl, transport=zeep.transports.Transport(session=session))

headers = {
    'user': USERNAME,
    'password': PASSWORD,
}

data = {
    'Version': "3.000",
    'EchoToken': '1234',
    'EchoData': '1',
}

ping = client.service.Ping(**data, _soapheaders=headers)
print(ping)