code: def _get_fov_type(fov):
      "Return a FOV from a string"
      oldFOV = fov
      fov = str(fov).upper()
      if fov in _FOVTYPES:
          return _FOVTYPES[fov]
      if fov[:10] == 'PERMISSIVE' and fov[10].isdigit() and fov[10] != '9':
          return 4 + int(fov[10])
      raise _tdl.TDLError('No such fov option as %s' % oldFOVf _get_fov_type(fov):
      "Return a FOV from a string"
      oldFOV = fov
      fov = str(fov).upper()
      if fov in _FOVTYPES:
          return _FOVTYPES[fov]
      if fov[:10] == 'PERMISSIVE' and fov[10].isdigit() and fov[10] != '9':
          return 4 + int(fov[10])
      raise _tdl.TDLError('No such fov option as %s' % oldFOV)
docs: Return a FOV from a string