protected boolean parseUnaryExpression(boolean isTargetExpression) {
    final IElementType tokenType = myBuilder.getTokenType();
    if (PyTokenTypes.UNARY_OPERATIONS.contains(tokenType)) {
      final SyntaxTreeBuilder.Marker expr = myBuilder.mark();
      myBuilder.advanceLexer();
      if (!parseUnaryExpression(isTargetExpression)) {
        myBuilder.error(message("PARSE.expected.expression"));
      }
      expr.done(PyElementTypes.PREFIX_EXPRESSION);
      return true;
    }
    else {
      return parsePowerExpression(isTargetExpression);
    }
  }
protected boolean parseUnaryExpression(boolean isTargetExpression)