Assertion Error

[Jagdish960]

Traceback (most recent call last):
File "/home/jagdish/Downloads/try/LoRaWAN/tx_ttn.py", line 40, in
lora = LoRaWANsend(False)
File "/home/jagdish/Downloads/try/LoRaWAN/tx_ttn.py", line 15, in init
super(LoRaWANsend, self).init(verbose)
File "/home/jagdish/Downloads/try/LoRaWAN/SX127x/LoRa.py", line 100, in init
self.rx_chain_calibration(calibration_freq)
File "/home/jagdish/Downloads/try/LoRaWAN/SX127x/LoRa.py", line 856, in rx_chain_calibration
self.set_freq(freq_bkup)
File "/home/jagdish/Downloads/try/LoRaWAN/SX127x/LoRa.py", line 282, in set_freq
assert self.mode == MODE.SLEEP or self.mode == MODE.STDBY or self.mode == MODE.FSK_STDBY
AssertionError
Not able to solve this error. Please help.