Fix EC Input error when calibration temperature is None

mycodo/inputs/atlas_ec.py

@@ -261,22 +261,26 @@ def get_measurement(self):
                 _, unit, _ = return_measurement_info(
                     device_measurement, conversion)
 
-                if unit != "C":
-                    out_value = convert_from_x_to_y_unit(
-                        unit, "C", last_measurement[1])
+                if last_measurement[1] is None:
+                    self.logger.error("Cannot use calibration temperature because it returned None. "
+                                      "Fix your temperature measurement and try again.")
                 else:
-                    out_value = last_measurement[1]
-
-                self.logger.debug(
-                    "Latest temperature used to calibrate: {temp}".format(
-                        temp=out_value))
-
-                ret_value, ret_msg = self.atlas_command.calibrate(
-                    'temperature', set_amount=out_value)
-                time.sleep(0.5)
-
-                self.logger.debug("Calibration returned: {val}, {msg}".format(
-                    val=ret_value, msg=ret_msg))
+                    if unit != "C":
+                        out_value = convert_from_x_to_y_unit(
+                            unit, "C", last_measurement[1])
+                    else:
+                        out_value = last_measurement[1]
+
+                    self.logger.debug(
+                        "Latest temperature used to calibrate: {temp}".format(
+                            temp=out_value))
+
+                    ret_value, ret_msg = self.atlas_command.calibrate(
+                        'temperature', set_amount=out_value)
+                    time.sleep(0.5)
+
+                    self.logger.debug("Calibration returned: {val}, {msg}".format(
+                        val=ret_value, msg=ret_msg))
             else:
                 self.logger.error(
                     "Calibration measurement not found within the past "