code: def write_compounds(self, stream, compounds, properties=None):
          
          self._write_entries(
              stream, compounds, self.convert_compound_entry, properties)
docs: Write iterable of compounds as YAML object to stream.
  
          Args:
              stream: File-like object.
              compounds: Iterable of compound entries.
              properties: Set of compound properties to output (or None to output
                  all).