code: def test_pop(self):
      fa = FieldArray(
          "y", [[1.1, 2.2, 3.3, 4.4, 5.5], [1.0, 2.0, 3.0, 4.0, 5.0]]
      )
      fa.pop(0)
      assert len(fa) == 1
      assert fa[0] == [1.0, 2.0, 3.0, 4.0, 5.0]
      fa[0] = [1.1, 2.2, 3.3, 4.4, 5.5]
      assert fa[0] == [1.1, 2.2, 3.3, 4.4, 5.5]
  
imports: import os
  import pytest
  import numpy
  from fastNLP.core.dataset import DataSet, FieldArray, Instance, ApplyResultException
  from fastNLP import logger
label_desc: Use image node_id 5 for calling the TestFieldArray obj's underlying member method code with example usage: obj.test_pop() without return types