code: def build_pattern(self):
      return "|".join(build_pattern(self.mapping))
  
file_path: catboost/contrib/tools/python/src/Lib/lib2to3/fixes/fix_imports.py
imports: from ..None import fixer_base
  from ..fixer_util import Name, attr_chain
label_desc: Use image node_id 1 for calling the FixImports obj's underlying member method code with example usage: obj.build_pattern() and returns: str