Added receive_n_data function

Allows for an in-between step between receive_data (most recent value only) and receive_all_data (all data values)

Author: kavinaidoo

adafruit_io/adafruit_io.py

@@ -53,6 +53,16 @@ def validate_feed_key(feed_key: str):
             "Feed key must contain English letters, numbers, dash, and a period or a forward slash."
         )
 
+def validate_n_values(n_values: int):
+    """Validates a provided number of values to retrieve data from Adafruit IO.
+
+    Although Adafruit IO will accept values < 1 and > 1000, this avoids two types of issues:
+    <1      - Coding errors
+    >1000   - Pagination-related expectation management
+
+    """
+    if n_values < 1 or n_values > 1000:  # validate 0 < n_values <= 1000
+        raise ValueError("Number of values must be greater than zero and less than or equal to 1000")
 
 class IO_MQTT:
     """
@@ -632,6 +642,18 @@ def receive_all_data(self, feed_key: str):
         validate_feed_key(feed_key)
         path = self._compose_path("feeds/{0}/data".format(feed_key))
         return self._get(path)
+    
+    def receive_n_data(self, feed_key: str, n_values: int):
+        """
+        Get n data values from a specified Adafruit IO feed. Data is
+        returned in reverse order.
+
+        :param str feed_key: Adafruit IO feed key
+        """
+        validate_n_values(n_values)
+        validate_feed_key(feed_key)
+        path = self._compose_path("feeds/{0}/data?limit={1}".format(feed_key,n_values))
+        return self._get(path)
 
     def receive_data(self, feed_key: str):
         """