public PlanMatchPattern withExactAssignments(
      Collection<? extends RvalueMatcher> expectedAliases) {
    matchers.add(new StrictAssignedSymbolsMatcher(actualAssignments(), expectedAliases));
    return this;
  }
Matches to any tree of nodes with children matching to given source matchers.
anyTree(tableScan("nation")) - will match to any plan which all leafs contain any node
containing table scan from nation table.

<p>Note: anyTree does not match zero nodes. E.g. output(anyTree(tableScan)) will NOT match
TableScan node followed by OutputNode.
iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/relational/planner/assertions/PlanMatchPattern.java