diff --git a/src/index.ts b/src/index.ts
index 9574356..19c6376 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -21,9 +21,9 @@ function isOptional(type: String): boolean {
   return type.startsWith('Optional[')
 }
 
-function toPythonTypeX(type: XtpNormalizedType): string {
+function toPythonTypeX(type: XtpNormalizedType, required: boolean = true): string {
   const opt = (t: string) => {
-    return type.nullable ? `Optional[${t}]` : t
+    return type.nullable || required === false ? `Optional[${t}]` : t
   }
   switch (type.kind) {
     case 'string':
@@ -64,12 +64,12 @@ function toPythonTypeX(type: XtpNormalizedType): string {
 }
 
 
-function toPythonType(property: XtpTyped): string {
-  return toPythonTypeX(property.xtpType);
+function toPythonType(property: XtpTyped, required?: boolean): string {
+  return toPythonTypeX(property.xtpType, required === true ? true : false);
 }
 
-function toPythonParamType(property: XtpTyped): string {
-  let t = toPythonTypeX(property.xtpType);
+function toPythonParamType(property: XtpTyped, required?: boolean): string {
+  let t = toPythonTypeX(property.xtpType, required);
   // We need to represent bare int/float as a str in Python for now,
   // there may be some updates to the encoder we can make to handle
   // this case at some point
diff --git a/template/plugin/pdk_types.py.ejs b/template/plugin/pdk_types.py.ejs
index 5054b1e..e6f24e7 100644
--- a/template/plugin/pdk_types.py.ejs
+++ b/template/plugin/pdk_types.py.ejs
@@ -18,20 +18,20 @@ class <%- pythonTypeName(schema.name) %>(Enum):
 @dataclass
 class <%- pythonTypeName(schema.name) %>(extism.Json):
 <% schema.properties.forEach(p => { -%>
-<% if (!p.nullable || p.required) {%>
+<% if (!p.nullable && p.required) {%>
   <% if (p.description) { -%>
     # <%- formatCommentBlock(p.description, "# ") %>
   <% } -%>
-  <%- p.name %>: <%- toPythonType(p) %>
+  <%- p.name %>: <%- toPythonType(p, p.required) %>
 <% } %>
 <% }) %>
 
 <% schema.properties.forEach(p => { -%>
-<% if (p.nullable && !p.required) {%>
+<% if (p.nullable || !p.required) {%>
   <% if (p.description) { -%>
     # <%- formatCommentBlock(p.description, "# ") %>
   <% } -%>
-  <%- p.name %>: <%- toPythonType(p) %> = None
+  <%- p.name %>: <%- toPythonType(p, p.required) %> = None
 <% } %>
 <% }) %>
 
diff --git a/tests/schemas/fruit.yaml b/tests/schemas/fruit.yaml
index bdf0d1f..4ba0c62 100644
--- a/tests/schemas/fruit.yaml
+++ b/tests/schemas/fruit.yaml
@@ -39,6 +39,16 @@ exports:
       contentType: application/json
       $ref: "#/components/schemas/ComplexObject"
 imports:
+  eatAString:
+    input:
+      contentType: text/plain; charset=utf-8
+      type: string
+    output:
+      contentType: text/plain; charset=utf-8
+      type: string
+    description: |
+      This is a host function. Right now host functions can only be the type (i64) -> i64.
+      We will support more in the future. Much of the same rules as exports apply.
   eatAFruit:
     input:
       contentType: text/plain; charset=utf-8
@@ -117,4 +127,13 @@ components:
         writeParams:
           "$ref": "#/components/schemas/WriteParams"
           nullable: true
+        aMapOfNullableDateTimes:
+          additionalProperties:
+            type: string
+            format: date-time
+            nullable: true
+      required:
+        - aBoolean
+        - aString
+        - writeParams
       description: A complex json object