code: def optimizer(self):
      return BinaryPSO
  
file_path: pyswarms/tests/optimizers/test_binary.py
imports: import pytest
  import numpy
  from pyswarms.discrete import BinaryPSO
  from pyswarms.utils.functions.single_obj import sphere
  from .abc_test_discrete_optimizer import ABCTestDiscreteOptimizer
label_desc: Use image node_id 1 for calling the TestDiscreteOptimizer obj's underlying member method code with example usage: obj.optimizer() and returns: BinaryPSO