The phrase .contain.all takes a range, all elements of which are expected to appear in the range on the left hand side.
The phrase .contain.any takes a range, at least one element of which is expected to appear in the range on the left hand side.
The word .contain takes one value, expected to appear in the range on the left hand side.
The phrase .contain.exactly indicates that two ranges are expected to contain exactly the same elements, but possibly in a different order.
The phrase .contain.only or .only.contain takes a range, the elements of which are expected to be the only elements appearing in the range on the left hand side.