fix broken vph tests (#533)

src/vivarium/component.py

@@ -603,6 +603,10 @@ def build_lookup_table(
             If the data source is invalid.
         """
         data = self.get_data(builder, data_source)
+        # TODO update this to use vivarium.types.LookupTableData once we drop
+        #  support for Python 3.9
+        if not isinstance(data, (Number, timedelta, datetime, pd.DataFrame, list, tuple)):
+            raise ConfigurationError(f"Data '{data}' must be a LookupTableData instance.")
 
         if isinstance(data, list):
             return builder.lookup.build_table(data, value_columns=list(value_columns))
@@ -656,7 +660,7 @@ def get_data(
         self,
         builder: Builder,
         data_source: LookupTableData | str | Callable[[Builder], LookupTableData],
-    ) -> float | pd.DataFrame:
+    ) -> Any:
         """Retrieves data from a data source.
 
         If the data source is a float or a DataFrame, it is treated as the data
@@ -683,12 +687,7 @@ def get_data(
         layered_config_tree.exceptions.ConfigurationError
             If the data source is invalid.
         """
-        # TODO update this to use vivarium.types.LookupTableData once we drop
-        #  support for Python 3.9
-        valid_data_types = (Number, timedelta, datetime, pd.DataFrame, list, tuple)
-        if isinstance(data_source, valid_data_types):
-            data = data_source
-        elif isinstance(data_source, str):
+        if isinstance(data_source, str):
             if "::" in data_source:
                 module, method = data_source.split("::")
                 try:
@@ -716,15 +715,8 @@ def get_data(
         elif isinstance(data_source, Callable):
             data = data_source(builder)
         else:
-            raise ConfigurationError(
-                f"Data source is of type '{type(data_source)}'. It must be a "
-                "LookupTableData instance, a string corresponding to an "
-                "artifact key, a callable that returns a LookupTableData "
-                "instance, or a string defining such a callable."
-            )
+            data = data_source
 
-        if not isinstance(data, valid_data_types):
-            raise ConfigurationError(f"Data '{data}' must be a LookupTableData instance.")
         return data
 
     def _set_population_view(self, builder: "Builder") -> None:

src/vivarium/framework/state_machine.py

@@ -27,10 +27,6 @@
     from vivarium.types import ClockTime, LookupTableData
 
 
-def default_initializer(_builder: Builder) -> LookupTableData:
-    return 0.0
-
-
 def _next_state(
     index: pd.Index,
     event_time: ClockTime,
@@ -221,7 +217,7 @@ def __init__(
         self,
         state_id: str,
         allow_self_transition: bool = False,
-        initialization_weights: Callable[[Builder], LookupTableData] = default_initializer,
+        initialization_weights: Callable[[Builder], LookupTableData] | None = None,
     ) -> None:
         super().__init__()
         self.state_id = state_id
@@ -294,7 +290,10 @@ def allow_self_transitions(self) -> None:
     ##################
 
     def get_initialization_weights(self, builder: Builder) -> LookupTableData:
-        return self.initialization_weights(builder)
+        if self.initialization_weights:
+            return self.initialization_weights(builder)
+        else:
+            return 0.0
 
     def transition_side_effect(self, index: pd.Index, event_time: ClockTime) -> None:
         pass
@@ -516,7 +515,7 @@ def __init__(
             self.add_states(states)
 
         states_with_initialization_weights = [
-            s for s in self.states if s.initialization_weights != default_initializer
+            state for state in self.states if state.initialization_weights
         ]
 
         if initial_state is not None:
@@ -533,7 +532,12 @@ def __init__(
 
             initial_state.initialization_weights = lambda _builder: 1.0
 
-        elif not states_with_initialization_weights:
+        # TODO: [MIC-5403] remove this on_initialize_simulants check once
+        #  VPH's DiseaseModel has a compatible initialization strategy
+        elif (
+            type(self).on_initialize_simulants == Machine.on_initialize_simulants
+            and not states_with_initialization_weights
+        ):
             raise ValueError(
                 "Must specify either an initial state or provide"
                 " initialization weights to states."

src/vivarium/framework/values/pipeline.py

@@ -186,6 +186,9 @@ def _call(self, *args: Any, skip_post_processor: bool = False, **kwargs: Any) ->
     def __repr__(self) -> str:
         return f"_Pipeline({self.name})"
 
+    def __hash__(self) -> int:
+        return hash(self.name)
+
     def get_value_modifier(
         self, modifier: Callable[..., Any], component: Component | None
     ) -> ValueModifier: