Add all the A tasks

Task/Averages-Simple-moving-average/Python/averages-simple-moving-average-2.py

@@ -0,0 +1,21 @@
+from collections import deque
+
+class Simplemovingaverage():
+    def __init__(self, period):
+        assert period == int(period) and period > 0, "Period must be an integer >0"
+        self.period = period
+        self.stream = deque()
+
+    def __call__(self, n):
+        stream = self.stream
+        stream.append(n)    # appends on the right
+        streamlength = len(stream)
+        if streamlength > self.period:
+            stream.popleft()
+            streamlength -= 1
+        if streamlength == 0:
+            average = 0
+        else:
+            average = sum( stream ) / streamlength
+
+        return average