    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.
File: contracts/Utilities/AccessControlMechanism.sol   #1

16:       mapping(bytes32 => mapping(address => bool)) public pendingRoles;
