text: # User Story 17: Siblings should not marry
  
  def US_18(listOfPeople):
      groupMap={}
      for people in listOfPeople:
          sp=people.Spouse.split(",")
          #print(sp)
          if people.Child not in groupMap and people.Child != "NA":
              groupMap[people.Child]=[]
              for obj in sp:
                  groupMap[people.Child].append(obj)
          elif people.Child in groupMap:
              for obj1 in sp:
                  if obj1!='NA':
                      groupMap[people.Child].append(obj1)
      #print(groupMap)
      for value in groupMap.values():
          #print(value)
          for i in value:
              if value.count(i)!=1:
                  print("ERROR: FAMILY: US18: in family"+" "+i+" "+"has married their sibilings")
                  a= False
                  break
              else:
                  a= True
      
      return a 
  