chore(CR): Added property, and added _read_sentsence

Author: billxinli

adafruit_gps.py

@@ -115,7 +115,7 @@ def __init__(self, uart, debug=False):
         self.total_mess_num = None
         self.mess_num = None
         self.debug = debug
-        self.sentence = None
+        self.raw_sentence = None
 
     def update(self):
         """Check for updated data from the GPS module and process it
@@ -176,7 +176,12 @@ def datetime(self):
         """Return struct_time object to feed rtc.set_time_source() function"""
         return self.timestamp_utc
 
-    def _parse_sentence(self):
+    @property
+    def raw_sentence(self):
+        """Return raw_sentence which is the raw NMEA sentence read from the GPS"""
+        return self.raw_sentence
+
+    def _read_sentence(self):
         # Parse any NMEA sentence that is available.
         # pylint: disable=len-as-condition
         # This needs to be refactored when it can be tested.
@@ -201,9 +206,21 @@ def _parse_sentence(self):
                 actual ^= ord(sentence[i])
             if actual != expected:
                 return None  # Failed to validate checksum.
-            self.sentence = sentence
-            # Remove checksum once validated.
-            sentence = sentence[:-3]
+
+            # copy the raw sentence
+            self.raw_sentence = sentence
+
+            return sentence
+
+    def _parse_sentence(self):
+        sentence = self._read_sentence()
+
+        # sentence is a valid NMEA with a valid checksum
+        if sentence is None:
+            return None
+
+        # Remove checksum once validated.
+        sentence = sentence[:-3]
         # Parse out the type of sentence (first string after $ up to comma)
         # and then grab the rest as data within the sentence.
         delimiter = sentence.find(',')