MobileAuthSerializer.py

class MobileAuthSerializer(serializers.Serializer):
	phone_number=serializers.CharField(required=True)
	def save(self):
		#Retrieve the user with this mobile number or create a user instance with that phone number
		try:
			user=User.objects.get(mobile=self.validated_data['phone_number'])
		except Exception as e:
			user=User.objects.create(mobile=self.validated_data['phone_number'],email=self.validated_data['phone_number'])

		#Generate the users token and send it out
		MobileToken.objects.filter(user=user).update(is_used=True)
		token=MobileToken.objects.create(
				user=user,
				verification_code=str(self.random_with_N_digits(7)),
				phone_number=self.validated_data['phone_number']
			)
		return token

		#method to generate jobs reference numbers
	def random_with_N_digits(self,n):
	    range_start = 10**(n-1)
	    range_end = (10**n)-1
	    return randint(range_start, range_end)