Fixes/upgrades

protocol/mizan-codegen/python/pydantic_to_rust/templates/struct.rs.j2

@@ -0,0 +1,38 @@
+{%- import "type.rs.j2" as types -%}
+{%- import "default.rs.j2" as defaults -%}
+{%- for line in doc_lines -%}
+/// {{ line }}
+{% endfor -%}
+#[derive({{ derives | join(", ") }})]
+{% for attr in extra_attrs -%}
+{{ attr }}
+{% endfor -%}
+pub struct {{ name }} {
+{%- for field in fields %}
+{%- if field.default_fn %}
+    #[serde(default = "{{ field.default_fn }}")]
+{%- endif %}
+    pub {{ field.ident }}: {{ types.rust_type(field.type) }},
+{%- endfor %}
+}
+
+{% for fn in default_fns -%}
+fn {{ fn.name }}() -> {{ types.rust_type(fn.type) }} { {{ defaults.default_body(fn.body) }} }
+{% endfor -%}
+{% if default_fns %}
+{% endif -%}
+{% if fields -%}
+impl Default for {{ name }} {
+    fn default() -> Self {
+        Self {
+{%- for field in fields %}
+{%- if field.default_fn %}
+            {{ field.ident }}: {{ field.default_fn }}(),
+{%- else %}
+            {{ field.ident }}: ::std::default::Default::default(),
+{%- endif %}
+{%- endfor %}
+        }
+    }
+}
+{% endif -%}