code: def _valid_flex_tuple(s):
      """Returns True if s is a tuple of the form (shots, copies)."""
      return (
          isinstance(s, tuple)
          and len(s) == 2
          and _valid_flex_int(s[0])
          and isinstance(s[1], int)
          and s[1] > 0
      )
  
imports: from random import shuffle
  import pytest
  import numpy
  import pennylane
  from pennylane.devices.qubit import simulate
  from pennylane.devices.qubit.simulate import _FlexShots
  from pennylane.devices.qubit import sample_state, measure_with_samples
  from pennylane.devices.qubit.sampling import _sample_state_jax
  from pennylane.measurements import Shots
label_desc: Use image node_id 3 for calling a global function with example usage: _valid_flex_tuple(s) and returns: unknown