code: def test_valid_marker(self, marker: str) -> None:
      # GIVEN
      to_parse = f"name; {marker}"
  
      # WHEN
      Requirement(to_parse)
  
imports: from typing import Optional, Set
  import pytest
  from packaging.markers import Marker
  from packaging.requirements import InvalidRequirement, Requirement
  from packaging.specifiers import SpecifierSet
label_desc: Use image node_id 1 for calling the TestRequirementParsing obj's underlying member method code with example usage: obj.test_valid_marker(marker) without return types