fix flake8 E275 missing whitespace after keyword

Author: cjekel

toleranceinterval/hk.py

@@ -94,16 +94,16 @@ def __init__(self, p, g, n, j, method='secant', max_iter=200,
         # create a dummy variable v
         self.v = Symbol('v', nonzero=True, rational=True, positive=True)
         # check that p, g, n, j are valid
-        if not(p < 0.5 and p > 0.):
+        if not (p < 0.5 and p > 0.):
             self.invalid_value(p, 'p')
         else:
             self.p = p
-        if not(g > 0. and g < 1.):
+        if not (g > 0. and g < 1.):
             self.invalid_value(g, 'g')
         else:
             self.g = g
         self.n = int(n)
-        if not(j < n and j > -1):
+        if not (j < n and j > -1):
             self.invalid_value(j, 'j')
         else:
             self.j = int(j)

toleranceinterval/twoside/_normal_exact.py

@@ -201,7 +201,7 @@ def tolerance_factor(n, coverage, confidence, m=None, nu=None, d2=None,
 
     # Handle the case of nu not being positive.
     if nu <= 0:
-        raise(ValueError, 'Degrees of freedom should be positive.')
+        raise (ValueError, 'Degrees of freedom should be positive.')
 
     # Compute the two-sided tolerance factor
     tol_high_precision = np.spacing(tailconfidence)