diff --git a/internal/jennies/python/builder.go b/internal/jennies/python/builder.go
index 909ea8255..d6774c388 100644
--- a/internal/jennies/python/builder.go
+++ b/internal/jennies/python/builder.go
@@ -87,8 +87,9 @@ func (jenny *Builder) generateBuilder(context languages.Context, builder ast.Bui
 	return jenny.tmpl.
 		Funcs(common.TypeResolvingTemplateHelpers(context)).
 		Funcs(map[string]any{
-			"formatType":    jenny.typeFormatter.formatType,
-			"formatRawType": jenny.rawTypeFormatter.formatType,
+			"isDisjunctionOfBuilders": context.IsDisjunctionOfBuilders,
+			"formatType":              jenny.typeFormatter.formatType,
+			"formatRawType":           jenny.rawTypeFormatter.formatType,
 			"formatRawTypeNotNullable": func(def ast.Type) string {
 				typeDef := def.DeepCopy()
 				typeDef.Nullable = false
diff --git a/internal/jennies/python/templates/builders/assignment.tmpl b/internal/jennies/python/templates/builders/assignment.tmpl
index 3a171f9f6..f698448c4 100644
--- a/internal/jennies/python/templates/builders/assignment.tmpl
+++ b/internal/jennies/python/templates/builders/assignment.tmpl
@@ -21,7 +21,12 @@
 {{- with .Value.Argument }}
 {{- if or (resolvesToBuilder .Type) (resolvesToComposableSlot .Type) }}
 {{- $builtResultSuffix := ternary "_resources" "_resource" (or .Type.IsArray .Type.IsMap) }}
-{{ .Name|formatIdentifier }}{{ $builtResultSuffix }} = {{ template "unfold_builders" (dict "InputType" .Type "InputVar" (formatIdentifier .Name) "Depth" 1) }}
+{{- $name := print (.Name|formatIdentifier) $builtResultSuffix }}
+{{ $name }} = {{ template "unfold_builders" (dict "InputType" .Type "InputVar" (formatIdentifier .Name) "Depth" 1) }}
+{{- if and .Type.IsDisjunction (not (isDisjunctionOfBuilders .Type)) }}
+{{ $branchesCount := sub1 (len .Type.Disjunction.Branches) -}}
+assert {{ range $i, $branch := .Type.Disjunction.Branches }}isinstance({{ $name }}, {{ $branch|formatRawType}}){{ if ne $i $branchesCount }} or {{ end }}{{ end -}}
+{{- end -}}
 {{- end }}
 {{- end }}
 {{- with .Value.Envelope }}
@@ -36,6 +41,8 @@
 [{{ template "unfold_builders" (dict "InputType" .InputType.Array.ValueType "InputVar" (print "r" .Depth ) "Depth" (add1 .Depth)) }} for r{{ .Depth }} in {{ .InputVar }}]
 {{- else if .InputType.IsMap -}}
 { key{{.Depth}}: {{ template "unfold_builders" (dict "InputType" .InputType.Map.ValueType "InputVar" (print "val" .Depth ) "Depth" (add1 .Depth)) }} for (key{{.Depth}}, val{{ .Depth }}) in {{ .InputVar }}.items() }
+{{- else if and .InputType.IsDisjunction (not (isDisjunctionOfBuilders .InputType)) -}}
+{{ .InputVar }}.build() if hasattr({{ .InputVar }}, 'build') and callable({{ .InputVar }}.build) else {{ .InputVar }}
 {{- else -}}
 {{ .InputVar }}.build()
 {{- end -}}
diff --git a/internal/jennies/python/tmpl.go b/internal/jennies/python/tmpl.go
index 16eb40805..8683cf221 100644
--- a/internal/jennies/python/tmpl.go
+++ b/internal/jennies/python/tmpl.go
@@ -24,6 +24,9 @@ func initTemplates(apiRefCollector *common.APIReferenceCollector, extraTemplates
 		template.Funcs(formattingTemplateFuncs()),
 		// placeholder functions, will be overridden by jennies
 		template.Funcs(template.FuncMap{
+			"isDisjunctionOfBuilders": func(_ ast.Type) string {
+				panic("isDisjunctionOfBuilders() needs to be overridden by a jenny")
+			},
 			"formatType": func(_ ast.Type) string {
 				panic("formatType() needs to be overridden by a jenny")
 			},
diff --git a/testdata/jennies/builders/builder_delegation_in_disjunction/PythonBuilder/builders/builder_delegation_in_disjunction.py b/testdata/jennies/builders/builder_delegation_in_disjunction/PythonBuilder/builders/builder_delegation_in_disjunction.py
index fbb64a265..9d02dfc23 100644
--- a/testdata/jennies/builders/builder_delegation_in_disjunction/PythonBuilder/builders/builder_delegation_in_disjunction.py
+++ b/testdata/jennies/builders/builder_delegation_in_disjunction/PythonBuilder/builders/builder_delegation_in_disjunction.py
@@ -61,7 +61,8 @@ def single_link_or_string(self, single_link_or_string: typing.Union[cogbuilder.B
         will be expanded to cog.Builder<DashboardLink> | string
         """
             
-        single_link_or_string_resource = single_link_or_string.build()
+        single_link_or_string_resource = single_link_or_string.build() if hasattr(single_link_or_string, 'build') and callable(single_link_or_string.build) else single_link_or_string
+        assert isinstance(single_link_or_string_resource, builder_delegation_in_disjunction.DashboardLink) or isinstance(single_link_or_string_resource, str)
         self._internal.single_link_or_string = single_link_or_string_resource
     
         return self
@@ -71,7 +72,7 @@ def links_or_strings(self, links_or_strings: list[typing.Union[cogbuilder.Builde
         will be expanded to [](cog.Builder<DashboardLink> | string)
         """
             
-        links_or_strings_resources = [r1.build() for r1 in links_or_strings]
+        links_or_strings_resources = [r1.build() if hasattr(r1, 'build') and callable(r1.build) else r1 for r1 in links_or_strings]
         self._internal.links_or_strings = links_or_strings_resources
     
         return self