docs: def EncodeMultipartFormData(fields, files):
  	"""Encode form fields for multipart/form-data.
  
  	Args:
  		fields: A sequence of (name, value) elements for regular form fields.
  		files: A sequence of (name, filename, value) elements for data to be
  					uploaded as files.
  	Returns:
  		(content_type, body) ready for httplib.HTTP instance.
  
  	Source:
  		http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/146306
  	"""
  	BOUNDARY = '-M-A-G-I-C---B-O-U-N-D-A-R-Y-'
  	CRLF = '\r\n'
  	lines = []
  	for (key, value) in fields:
  		typecheck(key, str)
  		typecheck(value, str)
  		lines.append('--' + BOUNDARY)
  		lines.append('Content-Disposition: form-data; name="%s"' % key)
  		lines.append('')
  		lines.append(value)
  	for (key, filename, value) in files:
  		typecheck(key, str)
  		typecheck(filename, str)
  		typecheck(value, str)
  		lines.append('--' + BOUNDARY)
  		lines.append('Content-Disposition: form-data; name="%s"; filename="%s"' % (key, filename))
  		lines.append('Content-Type: %s' % GetContentType(filename))
  		lines.append('')
  		lines.append(value)
  	lines.append('--' + BOUNDARY + '--')
  	lines.append('')
  	body = CRLF.join(lines)
  	content_type = 'multipart/form-data; boundary=%s' % BOUNDARY
  	return content_type, body