def load_pip_requirements(self, files_map=None, freeze=True):
        if files_map is None:
            files_map = self.default_pip_files
        for group, requirements_txt in files_map.items():
            path = Path(requirements_txt)
            if not path.exists() and group.lower() == "all" and freeze:
                cmd = envoy.run("pip freeze")
                self[group].loads(cmd.std_out)
            elif path.exists():
                self[group].load(path)
def _read_flo(file_name):
    """Read .flo file in Middlebury format"""
    # Code adapted from:
    # http://stackoverflow.com/questions/28013200/reading-middlebury-flow-files-with-python-bytes-array-numpy
    # Everything needs to be in little Endian according to
    # https://vision.middlebury.edu/flow/code/flow-code/README.txt
    with open(file_name, "rb") as f:
        magic = np.fromfile(f, "c", count=4).tobytes()
        if magic != b"PIEH":
            raise ValueError("Magic number incorrect. Invalid .flo file")

        w = int(np.fromfile(f, "<i4", count=1))
        h = int(np.fromfile(f, "<i4", count=1))
        data = np.fromfile(f, "<f4", count=2 * w * h)
        return data.reshape(h, w, 2).transpose(2, 0, 1)