import urllib2
boundary = '85fc538bf62b'
data = """--{0}
Content-Disposition: form-data; name="param_name"
param_value
--{0}--
""".format(boundary)
request = urllib2.Request('http://google.com', data=data, headers={'Content-Type': 'multipart/form-data; boundary={0}'.format(boundary)})
response = urllib2.urlopen(request).read()