Method operator()

tests/test_buffers.cpp:239–241

        }

        float operator()(py::ssize_t i, py::ssize_t j) const {
            return Matrix::operator()(i * m_row_factor, j * m_col_factor);
        }

        float &operator()(py::ssize_t i, py::ssize_t j) {
            return Matrix::operator()(i * m_row_factor, j * m_col_factor);