Workaround terra mpl drawer bug

mtreinish · mtreinish · commit db28762643e3 · 2020-05-04T18:10:37.000-04:00
There is a bug in the mpl drawer in 0.19.0 (and 0.19.1) release where a
custom instruction does not draw without a label parameter set. This
will need to be fixed in terra, but in the meantime this worksaround the
bug by manually setting a label.
diff --git a/tutorials/terra/advanced/1_advanced_circuits.ipynb b/tutorials/terra/advanced/1_advanced_circuits.ipynb
@@ -147,6 +147,7 @@
     "\n",
     "# Convert to a gate and stick it into an arbitrary place in the bigger circuit\n",
     "sub_inst = sub_circ.to_instruction()\n",
+    "sub_inst.label = "sub_circ\n",
     "\n",
     "q = QuantumRegister(3, 'q')\n",
     "circ = QuantumCircuit(q)\n",
