Python: Improve some flow summaries

python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPrivate.qll

@@ -1138,7 +1138,9 @@ predicate clearsContent(Node n, ContentSet cs) {
  * Holds if the value that is being tracked is expected to be stored inside content `c`
  * at node `n`.
  */
-predicate expectsContent(Node n, ContentSet c) { none() }
+predicate expectsContent(Node n, ContentSet c) {
+  FlowSummaryImpl::Private::Steps::summaryExpectsContent(n.(FlowSummaryNode).getSummaryNode(), c)
+}
 
 /**
  * Holds if values stored inside attribute `c` are cleared at node `n`.

python/ql/lib/semmle/python/dataflow/new/internal/FlowSummaryImpl.qll

@@ -91,6 +91,8 @@ module Input implements InputSig<Location, DataFlowImplSpecific::PythonDataFlow>
     cs.isAnyTupleOrDictionaryElement() and result = "AnyTupleOrDictionaryElement" and arg = ""
   }
 
+  string encodeWithContent(ContentSet c, string arg) { result = "With" + encodeContent(c, arg) }
+
   bindingset[token]
   ParameterPosition decodeUnknownParameterPosition(AccessPath::AccessPathTokenBase token) {
     // needed to support `Argument[x..y]` ranges