pyvisa with GPIB

Question

I need to control an equipment from Agilent via GPIB under python in ubuntu 20.04. I have installed the visa libraries from Keysight, also from national and pyvisa-py, but when I cannot manage the device. When I check the pyvisa-info i obtain:

/usr/local/lib/python3.8/dist-packages/gpib_ctypes/gpib/gpib.py:54: UserWarning: GPIB library not found. Please manually load it using _load_lib(filename). All GPIB functions will raise OSError until the library is manually loaded.
  warnings.warn(message)
Machine Details:
   Platform ID:    Linux-5.15.0-67-generic-x86_64-with-glibc2.29
   Processor:      x86_64

Python:
   Implementation: CPython
   Executable:     /usr/bin/python3.8
   Version:        3.8.10
   Compiler:       GCC 9.4.0
   Bits:           64bit
   Build:          Nov 14 2022 12:59:47 (#default)
   Unicode:        UCS4

PyVISA Version: 1.13.0

Backends:
   ivi:
      Version: 1.13.0 (bundled with PyVISA)
      #1: /usr/lib/x86_64-linux-gnu/libvisa.so.22.5.0:
         found by: auto
         bitness: 64
         Vendor: National Instruments
         Impl. Version: 23069952
         Spec. Version: 5244928
   py:
      Version: 0.6.3
      ASRL INSTR: Available via PySerial (3.5)
      USB INSTR: Available via PyUSB (1.2.1). Backend: libusb1
      USB RAW: Available via PyUSB (1.2.1). Backend: libusb1
      TCPIP INSTR: Available 
         Resource discovery:
         - VXI-11: ok
         - hislip: ok
      VICP INSTR:
         Please install PyVICP to use this resource type.
      TCPIP SOCKET: Available 
      GPIB INSTR:
         gpib_ctypes is installed but could not locate the gpib library.
         Please manually load it using:
           gpib_ctypes.gpib.gpib._load_lib(filename)
         before importing pyvisa.

It seems that the problem is that gpib_ctypes does not found the gpib library, I tried to install, but the repository does not be available.

I just install the VIsa of NI (ni-visa and ni-4883) also try to compile the gpib library but nothing work

Any sugerence? thank you!