input: Write a python function to extract crew member details.
  assert isinstance(GetMembersList(driver), list)
  assert all(isinstance(member, crew_member) for member in GetMembersList(driver))
  assert len(GetMembersList(driver)) >= 0
output: def GetMembersList(driver):
      class crew_member:
          def __init__(self, name, role):
              self.name = name
              self.role = role
  
      members = []
      member_elements = driver.find_elements_by_class_name('crew-member')
      
      for element in member_elements:
          name = element.find_element_by_class_name('name').text
          role = element.find_element_by_class_name('role').text
          members.append(crew_member(name, role))
      
      return members