def FindFileContainingSymbol(self, symbol):
return self._file_desc_protos_by_symbol[symbol]<EOL>
Finds the file descriptor proto containing the specified symbol.

        The symbol should be a fully qualified name including the file descriptor's
        package and any containing messages. Some examples:

        'some.package.name.Message'
        'some.package.name.Message.NestedEnum'

        The file descriptor proto containing the specified symbol must be added to
        this database using the Add method or else an error will be raised.

        Args:
          symbol: The fully qualified symbol name.

        Returns:
          The file descriptor proto containing the symbol.

        Raises:
          KeyError if no file contains the specified symbol.