def get_expr_params(operator):
 if (operator.type == lo.PARAM):
  return operator.data.parameters()
 else:
  params = []
  for arg in operator.args:
   params += get_expr_params(arg)
  if isinstance(operator.data, lo.LinOp):
   params += get_expr_params(operator.data)
  return params

def get_expr_params ( operator ) : if ( operator . type == lo . PARAM ) : return operator . data . parameters ( ) else : params = [ ] for arg in operator . args : params += get_expr_params ( arg ) if isinstance ( operator . data , lo . LinOp ) : params += get_expr_params ( operator . data ) return params
get a list of the parameters in the operator .