This function returns all tie chains in components. A tie chain may not encompass all the leaves spanned by its corresponding Tie spanner, but only those found in the given list. i.e. the function returns the intersection between all the leav es spanned by all tie spanners touching the components given and the leaves found in the given components list.
Changed in version 2.0: renamed tietools.get_tie_chains() to tietools.get_tie_chains_in_expr().