I am running my old qiskit code after a very long time it's not running now showing error wrong color format 'ansibrightred' and I don't know why?
from qiskit import QuantumCircuit, QuantumRegister, ClassicalRegister
circuit = QuantumCircuit(2,2)
circuit.h(0)
circuit.cx(0,1)
circuit.measure([0,1], [0,1])
That error is caused by running qiskit-terra 0.13.0 with pygments installed, but below the optional dependency minimum version of 2.4: https://github.com/Qiskit/qiskit-terra/blob/master/setup.py#L117. However, you've found a bug in terra, an error should only be shown if you are using the optional functionality (circuit.qasm() with formatted=True set or using the circuit library jupyter widget). I've pushed up a fix to address this edge case in: https://github.com/Qiskit/qiskit-terra/pull/4229
In the meantime while waiting for that to get into a release, you can workaround this issue by either installing pygments>=2.4 or uninstalling pygments. Either will fix the error.
