extractor-objects.md: Option[Seq[T]] is useful when the number of values isn't fixed

Author: jbalintbiro

_tour/extractor-objects.md

@@ -57,4 +57,4 @@ The return type of an `unapply` should be chosen as follows:
 * If it returns a single sub-value of type T, return an `Option[T]`
 * If you want to return several sub-values `T1,...,Tn`, group them in an optional tuple `Option[(T1,...,Tn)]`.
 
-Sometimes, the number of sub-values is fixed and we would like to return a sequence. For this reason, you can also define patterns through `unapplySeq` which returns `Option[Seq[T]]` This mechanism is used for instance in pattern `case List(x1, ..., xn)`.
+Sometimes, the number of sub-values isn't fixed and we would like to return a sequence. For this reason, you can also define patterns through `unapplySeq` which returns `Option[Seq[T]]` This mechanism is used for instance in pattern `case List(x1, ..., xn)`.