Error: View Token hasn't been Generated Kindly Call the Login Function and Try to Generate OTP

[Cloudman0011]

try:
client = NeoAPI(consumer_key="", consumer_secret="", environment='prod', access_token=None)
client.login(mobilenumber="", password="")
client.session_2fa(OTP="")

except Exception as e:
print(e)

Its raising the following exception:
View Token hasn't been Generated Kindly Call the Login Function and Try to Generate OTP