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contracts...Heritage.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity 0.8.18;

/**
 *
 */
contract ParentContract {
    uint256 internal sensDeLaVie = 42;

    function setValue(uint256 _value) external {
        sensDeLaVie = _value;
    }
}

contract ChildContract is ParentContract {
    function getSensDeLaVie() external view returns (uint256) {
        return sensDeLaVie;
    }
}

contract Caller {
    ChildContract runner = new ChildContract();

    function testInheritance(uint256 _value) public returns (uint256) {
        runner.setValue(_value);
        return runner.getSensDeLaVie();
    }
}