code: def _get_lines(self, lines_map):
      key = os.path.relpath(self.filename, SRCDIR)
      lines = lines_map.get(key, {})
      return set(lines)
  
imports: import os
  from coverage.plugin import CoveragePlugin, FileTracer, FileReporter
  from coverage.files import canonical_filename
label_desc: Use image node_id 4 for calling the CythonFileReporter obj's underlying member method code with example usage: obj._get_lines(lines_map) and returns: set