import requests  # From package 'python-requests-2.12.4-1' in Debian stretch

def makeGenerator():
    yield 'Some data'

headers = {
    'Host': 'www.example.com',
}

response = requests.post('http://127.0.0.1:3000', data=makeGenerator(), headers=headers)
print(response)

# Produced output: (get it by running 'nc --vvlp 3000')

# listening on [any] 3000 ...
# connect to [127.0.0.1] from localhost [127.0.0.1] 36412
# POST / HTTP/1.1
# Host: 127.0.0.1:3000
# Connection: keep-alive
# Accept-Encoding: gzip, deflate
# Accept: */*
# User-Agent: python-requests/2.12.4
# Host: www.example.com
# Transfer-Encoding: chunked
#
# 9
# Some data
# 0