diff --git a/circuitpython/code/main.py b/circuitpython/code/main.py
index 70a661e..3075c2c 100644
--- a/circuitpython/code/main.py
+++ b/circuitpython/code/main.py
@@ -10,7 +10,6 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
 """
 ##########################
 # Weather and GPS logger #
@@ -41,8 +40,8 @@ TODO for v1 :
  * write data on flash drive (work-in-progress)
  * send data through UART (work-in-progress)
 """
-__version__ = 0.2
 __author__ = "arofarn"
+__version__ = 0.2
 
 #######################
 import time
@@ -115,13 +114,6 @@ class Data:
             self._gps_current_fix = int(time.monotonic())
             if gps.has_fix:
                 self._gps_last_fix = self._gps_current_fix
-                self.data['GPS']['time'] = TIME_FORMAT.format(
-                    gps.timestamp_utc.tm_year,
-                    gps.timestamp_utc.tm_mon,
-                    gps.timestamp_utc.tm_mday,
-                    gps.timestamp_utc.tm_hour,
-                    gps.timestamp_utc.tm_min,
-                    gps.timestamp_utc.tm_sec)
                 self.data['GPS']['lat'] = gps.latitude
                 self.data['GPS']['lon'] = gps.longitude
                 self.data['GPS']['alt'] = gps.altitude_m
@@ -135,34 +127,34 @@ class Data:
 
     def show(self):
         """Serialize data for visualization on serial console"""
-        for source in self.data.keys():
+        for source, val in self.data.items():
             print(source + ": ")
-            if not self.data[source] is None:
-                for d in self.data[source].items():
-                    print("\t{0}: {1}".format(d[0], d[1]))
+            if val is not None:
+                for name, value in val.items():
+                    print("\t{0}: {1}".format(name, value))
 
     @property
     def json(self):
         """Serialized data to compact json-formatted string"""
         output = '{'
         first_source = True
-        for source in self.data.keys():
+        for source, val in self.data.items():
             if first_source:
                 first_source = False
                 comma_src = ""
             else:
                 comma_src = ","
             output = '{}{}"{}":'.format(output, comma_src, source)
-            if not self.data[source] is None:
+            if val is not None:
                 output = output + '{'
                 first_data = True
-                for d in self.data[source].items():
+                for name, value in val.items():
                     if first_data:
                         comma = ""
                         first_data = False
                     else:
                         comma = ","
-                    output = '{}{}"{}":"{}"'.format(output, comma, d[0], d[1])
+                    output = '{}{}"{}":"{}"'.format(output, comma, name, value)
             output = output + '}'
         output = output + '}'
         return output
@@ -315,7 +307,7 @@ def measure_vbat(samples=10, timestep=0.01):
     #  3.3 : Vref = 3.3V
     #  65536 : 16bit ADC
     val = 0
-    for i in range(samples):
+    for sample in range(samples):
         val = val + vbat.value
         time.sleep(timestep)
     return val/samples*0.000100708