Removed unnecessary colon

pulse_lib/virtual_matrix/virtual_gate_matrix.py

@@ -47,7 +47,7 @@ class VirtualGateMatrix:
         if self._invert:
             matrix = np.linalg.inv(matrix)
         if self._valid_indices:
-            matrix = matrix[self._valid_indices, :]
+            matrix = matrix[self._valid_indices]
             if self._square:
                 matrix = matrix[:, self._valid_indices]
         return matrix