docs: def get_param(xmldoc, name):
  	"""
  	Scan xmldoc for a param named name.  Raises ValueError if not
  	exactly 1 such param is found.
  	"""
  	params = getParamsByName(xmldoc, name)
  	if len(params) != 1:
  		raise ValueError("document must contain exactly one %s param" % StripParamName(name))
  	return params[0]