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// This contract is part of Zellic’s smart contract dataset, which is a collection of publicly available contract code gathered as of March 2023.

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.9;

/**

 * @dev Interface of the ERC20 standard as defined in the EIP.

 */
interface IERC20 {
    // OPTIONAL public state variable getter is automatically generated.
    // function name() public view returns (string);
    // function symbol() public view returns (uint8);
    // function decimals() public view returns (uint256);

    /**

     * @return The amount of tokens in existence.

     */
    function totalSupply() external view returns (uint256);

    /**

     * @param account ? caller msg.sender ?

     * @return The amount of tokens owned by `account`.

     */
    function balanceOf(address account) external view returns (uint256);

    /**

     * @dev This is zero by default.

     * This value changes when {approve} or {transferFrom} are called.

     *

     * @return The remaining number of tokens that `spender` will be

     * allowed to spend on behalf of `owner` through {transferFrom}.

     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**

     * @dev Moves `amount` tokens from the caller's account to `to`.

     *

     * Emits a {Transfer} event.

     *

     * @return A boolean value indicating whether the operation succeeded.

     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**

     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.

     *

     * Emits an {Approval} event.

     *

     * IMPORTANT: Beware that changing an allowance with this method brings the risk

     * that someone may use both the old and the new allowance by unfortunate

     * transaction ordering. One possible solution to mitigate this race

     * condition is to first reduce the spender's allowance to 0 and set the

     * desired value afterwards:

     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729

     *

     * @return A boolean value indicating whether the operation succeeded.

     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**

     * @dev Moves `amount` tokens from `from` to `to` using the

     * allowance mechanism. `amount` is then deducted from the caller's

     * allowance.

     *

     * Emits a {Transfer} event.

     *

     * @return A boolean value indicating whether the operation succeeded.

     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);

    /**

     * @dev Emitted when `value` tokens are moved from one account (`from`) to

     * another (`to`).

     *

     * Note that `value` may be zero.

     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**

     * @dev Emitted when the allowance of a `spender` for an `owner` is set by

     * a call to {approve}.

     * `value` is the new allowance.

     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}