diff --git a/packages/pygsti/construction/circuitconstruction.py b/packages/pygsti/construction/circuitconstruction.py
index 8eb7590f1..f2798bdc6 100644
--- a/packages/pygsti/construction/circuitconstruction.py
+++ b/packages/pygsti/construction/circuitconstruction.py
@@ -472,7 +472,7 @@ def tolabel(x): return x if isinstance(x, _Lbl) else _Lbl(x)
 
     line_labels = prepStrs[0].line_labels if len(prepStrs) > 0 else 'auto'
     if line_labels is None or len(line_labels) == 0: line_labels = ('*',)
-    singleOps = [_cir.Circuit((gl,), line_labels=line_labels)**1 for gl in opLabels] # **1 adds parens to stringrep
+    singleOps = [_cir.Circuit((gl,), line_labels=line_labels)**1 for gl in opLabels]  # **1 adds parens to stringrep
     ret = create_circuit_list('eStr', 'prepStr', 'prepStr+eStr', 'prepStr+g+eStr',
                               eStr=effectStrs, prepStr=prepStrs, g=singleOps,
                               order=['g', 'prepStr', 'eStr'])  # LEXICOGRAPHICAL VS MATRIX ORDER
diff --git a/packages/pygsti/tools/optools.py b/packages/pygsti/tools/optools.py
index 9d7103831..e1188da8b 100644
--- a/packages/pygsti/tools/optools.py
+++ b/packages/pygsti/tools/optools.py
@@ -94,11 +94,12 @@ def fidelity(A, B):
 
     #if _np.array_equal(A, B): return 1.0  # HACK - some cases when A and B are perfecty equal sqrtm(A) fails...
     sqrtA = _hack_sqrtm(A)  # _spl.sqrtm(A)
-    #assert(_np.linalg.norm(_np.dot(sqrtA, sqrtA) - A) < 1e-8)  # test the scipy sqrtm function - sometimes fails when rank defficient
+    # test the scipy sqrtm function - sometimes fails when rank defficient
+    #assert(_np.linalg.norm(_np.dot(sqrtA, sqrtA) - A) < 1e-8)
     if _np.linalg.norm(_np.dot(sqrtA, sqrtA) - A) > 1e-8:
         evals = _np.linalg.eigvals(A)
-        _warning.warn(("sqrtm(A) failure when computing fidelity - beware result. "
-                       "Maybe due to rank defficiency - eigenvalues of A are: %s") % evals)
+        _warnings.warn(("sqrtm(A) failure when computing fidelity - beware result. "
+                        "Maybe due to rank defficiency - eigenvalues of A are: %s") % evals)
     F = (_mt.trace(_hack_sqrtm(_np.dot(sqrtA, _np.dot(B, sqrtA)))).real)**2  # Tr( sqrt{ sqrt(A) * B * sqrt(A) } )^2
     return float(F)