nRF9160 SDK compile error

Hello guys

I am trying to compile the latest nrf sdk with version v1.2.0 it fails with the following error

but when i compile either v1.0.0 or v1.1.0 it is successfully compiled

only v1.2.0 gives me this error any help please

root@ELB-iSCADA8m:/home/nick/Desktop/v1.2/nrf/samples/nrf9160/at_client# west build -b nrf9160_pca10090ns
Traceback (most recent call last):
  File "/root/.local/bin/west", line 8, in <module>
  File "/root/.local/lib/python3.5/site-packages/west/", line 583, in main
    args.handler(args, unknown)
  File "/root/.local/lib/python3.5/site-packages/west/", line 324, in ext_command_handler
    command = spec.factory()
  File "/root/.local/lib/python3.5/site-packages/west/commands/", line 365, in __call__
    mod = _commands_module_from_file(self.py_file)
  File "/root/.local/lib/python3.5/site-packages/west/commands/", line 333, in _commands_module_from_file
    mod = _import_mod_from(mod_name, file)
  File "/root/.local/lib/python3.5/site-packages/west/commands/", line 330, in _import_mod_from
  File "<frozen importlib._bootstrap_external>", line 665, in exec_module
  File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
  File "/home/nick/Desktop/v1.2/zephyr/scripts/west_commands/", line 15, in <module>
    from zephyr_ext_common import Forceable
  File "/home/nick/Desktop/v1.2/zephyr/scripts/west_commands/", line 14, in <module>
    from runners.core import RunnerConfig
  File "/home/nick/Desktop/v1.2/zephyr/scripts/west_commands/runners/", line 25, in <module>
    from runners import nrfjprog
  File "/home/nick/Desktop/v1.2/zephyr/scripts/west_commands/runners/", line 86
    f'refusing to guess which of {len(snrs)} '
SyntaxError: invalid syntax