PEP8 fixes

lambdas and imports

tests/test_dsp.py

@@ -1,12 +1,13 @@
 from amodem import dsp
 from amodem import sampling
 from amodem import config
-config = config.fastest()
 
 import numpy as np
 import random
 import itertools
 
+config = config.fastest()
+
 
 def test_linreg():
     x = np.array([1, 3, 2, 8, 4, 6, 9, 7, 0, 5])