def __init__(self, assets_dir=None, requirements_file="requirements.yml"):
        self.assets_dir = assets_dir or Path(".") / "assets"
        self.requirements = GroupedRequirements()
        self.requirements.load(requirements_file)
        self.temp_dir = mkdtemp()
def row_col(self, ind):
        i = 0
        for r in range(self.nr):
            for c in range(self.nc):
                if i == ind:
                    return r, c
                i += 1