Apply suggestions from code review

Co-authored-by: Simon Cross <hodgestar+github@gmail.com>

qutip/core/qobj.py

@@ -374,7 +374,7 @@ def to(self, data_type, copy=False):
         Parameters
         ----------
         data_type : type, str
-            The data-layer type or it's string alias that the data of this
+            The data-layer type or its string alias that the data of this
             :class:`Qobj` should be converted to.
 
         copy : Bool

qutip/entropy.py

@@ -372,6 +372,5 @@ def entangling_power(U):
     a = tensor(U, U).dag() * swap13 * tensor(U, U) * swap13
     Uswap = swap() * U
     b = tensor(Uswap, Uswap).dag() * swap13 * tensor(Uswap, Uswap) * swap13
-    print(a.tr(), b.tr())
 
     return 5.0/9 - 1.0/36 * (a.tr() + b.tr()).real

qutip/tests/test_entropy.py

@@ -209,6 +209,4 @@ def test_triangle_inequality_4_qubits(self):
                  np.sin(np.pi*_alpha)**2 / 6, id="SWAP(alpha)"),
 ])
 def test_entangling_power(gate, expected):
-    print("_alpha", _alpha)
-    print("gate", gate)
     assert abs(qutip.entangling_power(gate) - expected) < 1e-12