title: Where does a helper function go in pytest
body: <p>Given a helper function:</p>
  <pre><code>def reset_defaults(func):
      func.__defaults__ = ({},)
  </code></pre>
  <p>Which is used:</p>
  <pre><code>import pytest
  from src.DYNAMIC_PROGRAMMING.can_sum.can_sum import can_sum
  from tests.conftest import reset_defaults
  
  ...
  
  @pytest.mark.parametrize(&quot;target, numbers, sum_possible&quot;, test_cases, ids=ids)
  def test_can_sum(target, numbers, sum_possible):
      reset_defaults(can_sum)
      assert can_sum(target, numbers) == sum_possible
  </code></pre>
  <p>Is conftest file the right place to keep that helper function? Could it be organised better (by using a fixture for instance)?</p>