public ByteCodeBuilder returnValueAtMemory(final int size, final int key) {
    this.push(size).push(key).op(Operation.RETURN);
    return this;
  }
Operations to return the value at a given memory position

@param size size of the returned value
@param key location in memory of the returned value
@return this
evm/src/test/java/org/hyperledger/besu/evm/testutils/ByteCodeBuilder.java