def _buildParams(userInput):
    """ Takes a dictionary of user-inputted paramaters, where the keys are the names
	of the parameters in the URL and the values are either None or the value of the parameters
	in the URL."""
    params = '?'
    for key, value in userInput.items():
        if value != None:
            params += '%s=%s&' % (key, value)
    return params
