import requests
from requests_toolbelt.multipart.encoder import MultipartEncoder

multipart_data = MultipartEncoder(
    fields={
            # a file upload field
            'file': ('file.zip', open('file.zip', 'rb'), 'text/plain')
            # plain text fields
            'field0': 'value0', 
            'field1': 'value1',
           }
    )

response = requests.post('http://httpbin.org/post', data=multipart_data,
                  headers={'Content-Type': multipart_data.content_type})