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contracts...Elementary Data Types...BoolType.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;
 
contract BoolType {
   bool public aBool;
 
   function notBool() public view returns (bool) {
       return !aBool;
   }
 
   function isEqual(bool anotherBool) public view returns(bool) {
       return aBool == anotherBool;
   }
}