Changed make_filter back to just returning a function.

Author: Joseph Atkins-Turkish

signals.py

@@ -50,7 +50,10 @@ def make_filter(order=5, low_freq=0.75, high_freq=5, sample_freq=250.0):
     low = low_freq / nyq
     high = high_freq / nyq
     b, a = signal.butter(order, [low, high], btype='bandpass')
-    return (lambda x: signal.lfilter(b, a, x), b, a)
+    func = lambda x: signal.lfilter(b, a, x)
+    func.b = b
+    func.a = a
+    return func
 
 
 def find_periodicities(X, sample_freq=250.0):

tests.py

@@ -28,7 +28,7 @@ def test_get_peaks(self):
     def test_make_filter(self):
         """ Check that the bandpass filter function filters the correct signals.
         N.B graph must be checked by eye! """
-        filt, b, a = signals.make_filter(
+        filt = signals.make_filter(
             order=5, low_freq=0.75, high_freq=5, sample_freq=250.0)
         x, y = self.make_test_signal(250.0)