code: def _parse_from_incar(filename, key):
      
      dirname = os.path.dirname(filename)
      for f in os.listdir(dirname):
          if re.search(r"INCAR", f):
              warnings.warn("INCAR found. Using " + key + " from INCAR.")
              incar = Incar.from_file(os.path.join(dirname, f))
              if key in incar:
                  return incar[key]
              else:
                  return None
      return None
docs: Helper function to parse a parameter from the INCAR.