Before submitting the issue

• I have searched among the existing issues
• I am using a Python virtual environment

Description of the bug

When running the add_sweep_step under SetupCircuit, it reports an error as shown below

PyAEDT ERROR: **************************************************************
PyAEDT ERROR: File "c:\temp1\Untitled-1.py", line 12, in
PyAEDT ERROR: vtf_trans_setup.add_sweep_step(sweep_variable='Frequency', start=0, stop=20, step_size=0.5, units='GHz')
PyAEDT ERROR: 'sweepdefinition' on _add_sweep
PyAEDT ERROR: Last Electronics Desktop Message - [error] 'sweepdefinition' on _add_sweep

PyAEDT ERROR: Method arguments:
PyAEDT ERROR: sweep_variable = Frequency
PyAEDT ERROR: equation = LIN 0GHz 20GHz 0.5GHz
PyAEDT ERROR: override_existing_sweep = True
PyAEDT ERROR: **************************************************************

Steps To Reproduce

from pyaedt import Circuit

project_path = r'C:\temp1\circuit_tran.aedt'
project_name = 'Circuit1'

circuit = Circuit(version = "2025.2", project = project_path, design=project_name, non_graphical=False, new_desktop=False, close_on_exit=True)

vtf_trans_setup = circuit.create_setup(name="vtf_tran", setup_type="NexximTransient")

vtf_trans_setup.add_sweep_step(sweep_variable='Frequency', start=0, stop=20, step_size=0.5, units='GHz')
circuit.save_project()

Note: the "Frequency" is just a general variable in the Circuit design.

Which Operating System are you using?

Windows

Which Python version are you using?

3.10

Installed packages

pyaedt 0.21.2