code: def indent(self):
      self.indentlevel = self.indentlevel + 1
  
imports: from fontTools.misc.textTools import byteord, strjoin, tobytes, tostr
  import sys
  import os
  import string
label_desc: Use image node_id 16 for calling the XMLWriter obj's underlying member method code with example usage: obj.indent() without return types