list1.contains(null)
false

list1.contains(undefined)
false

list1.contains("A")
true

list1.contains("B")
true

list1.contains("C")
false

list1.contains(list1)
false

list1.contains(list2)
true

list1.contains(list3)
true

list1.contains(x)
true

list1.contains(x1)
true

list1.contains(x2)
true

list2.contains(null)
false

list2.contains(undefined)
false

list2.contains("A")
true

list2.contains("B")
false

list2.contains("C")
false

list2.contains(list1)
false

list2.contains(list2)
true

list2.contains(list3)
false

list2.contains(x)
true

list2.contains(x1)
true

list2.contains(x2)
false

list3.contains(null)
false

list3.contains(undefined)
false

list3.contains("A")
false

list3.contains("B")
true

list3.contains("C")
false

list3.contains(list1)
false

list3.contains(list2)
false

list3.contains(list3)
true

list3.contains(x)
false

list3.contains(x1)
false

list3.contains(x2)
true

x.contains(null)
false

x.contains(undefined)
false

x.contains("A")
false

x.contains("B")
false

x.contains("C")
false

x.contains(list1)
false

x.contains(list2)
false

x.contains(list3)
false

x.contains(x)
true

x.contains(x1)
true

x.contains(x2)
false

x1.contains(null)
false

x1.contains(undefined)
false

x1.contains("A")
false

x1.contains("B")
false

x1.contains("C")
false

x1.contains(list1)
false

x1.contains(list2)
false

x1.contains(list3)
false

x1.contains(x)
true

x1.contains(x1)
true

x1.contains(x2)
false

x2.contains(null)
false

x2.contains(undefined)
false

x2.contains("A")
false

x2.contains("B")
false

x2.contains("C")
false

x2.contains(list1)
false

x2.contains(list2)
false

x2.contains(list3)
false

x2.contains(x)
false

x2.contains(x1)
false

x2.contains(x2)
true

