contract Burnable {
  // @dev Destroys tokens for an account
  // @param account Account whose tokens are destroyed
  // @param value Amount of tokens to destroy
  function _burnTokens(address account, uint value) internal;
  event Burned(address account, uint value);
}
// Interface for burning tokens
function _burnTokens(address account, uint value) internal;

// @dev Destroys tokens for an account
// @param account Account whose tokens are destroyed
// @param value Amount of tokens to destroy