get the value under the 'indent' key of the options dictionary, multiply it with level, create a string containing number of whitespaces equal to the previous result, append it to the string containing newline character, use the result as the argument for the call to the self.xml.ignorableWhitespace method.
self . xml . ignorableWhitespace ( '\n' + ' ' * self . options . get ( 'indent' , None ) * level )