make the rebuild fn local

tests/test_metadata_roundtrips_via_simulation.py

@@ -23,8 +23,6 @@
 import msprime
 import pytest
 
-import rebuild_pdict
-
 
 @pytest.fixture
 def pdict(request):
@@ -201,7 +199,16 @@ def test_metadata_roundtrip_single_deme_sim_with_parameters(rng, pdict, pop, inc
     )
 
     provenance = json.loads(ts.provenance(0).record)
-    params_dict = rebuild_pdict.rebuild_pdict(provenance)
+
+    def rebuild_pdict(provenance):
+        import fwdpy11
+
+        for i in dir(fwdpy11):
+            exec(f"from fwdpy11 import {i}")
+        params_dict = eval(provenance["parameters"]["params_dict"])
+        return params_dict
+
+    params_dict = rebuild_pdict(provenance)
 
     assert params_dict == params.asdict()
     script = provenance["parameters"]["script"]