code: def init_backends():
      
  
      global _BACKENDS, _ACTIVE_BACKENDS
  
      try:
          from .cffi_backend import CFFIBackend
      except ImportError:
          pass
      else:
          _BACKENDS.append(CFFIBackend)
  
      from .ctypes_backend import CTypesBackend
      from .null_backend import NullBackend
  
      _BACKENDS.append(CTypesBackend)
      _ACTIVE_BACKENDS = _BACKENDS[:]
      # null isn't active by default
      _BACKENDS.append(NullBackend)
docs: Loads all backends