title: ValueError: option names {'--browser'} already added
body: <p><strong>pytest</strong> - I've been trying to run a command in the pycharm terminal to execute a pytest script. When tried to run the code its displaying error. <strong>raise ValueError("option names %s already added" % conflict)
      ValueError: option names {'--browser'} already added</strong>
      enter code here
      Command from terminal - py.test-v -s test_file.py --browser firefox</p>
  
  <pre><code>**test_file.py**
   import pytest
      def test_command_line_methodA(oneTimeSetUp, setUp):
           print("Running method A")
  
       def test_command_line_methodB(oneTimeSetUp, setUp):
            print("Running method B")
  
  **conftest.py**
   import pytest
  
     @pytest.yield_fixture()
         def setUp():
             print("Running method level setUp")
             yield
             print("Running method level tearDown")
  
  
      @pytest.yield_fixture(scope="module")
        def oneTimeSetUp(browser, osType):
           print("Running one time setUp")
           if browser == 'firefox':
              print("Running tests on FF")
             else:
               print("Running tests on chrome")
              yield
              print("Running one time tearDown")
  
              def pytest_addoption(parser):
                   parser.addoption("--browser")
                   parser.addoption("--osType", help="Type of operating 
      system")
  
              @pytest.fixture(scope="session")
                   def browser(request):
                      return request.config.getoption("--browser")
  
               @pytest.fixture(scope="session")
                   def osType(request):
                      return request.config.getoption("--osType")
  </code></pre>