Clojurians Log v2

I'm using malli for the first time and I'm confused about what schema types are available. Specifically, I'm not sure if I can use :inst or I have to use inst? in the schema. For example, this works:

(def DocumentMetadata
  [:map
   [:value_data_type {:description "The data type of the value"} :string]
   [:attribute_definition_id {:description "The UUID of the attribute definition"} :uuid]
   [:attribute_value {:description "The value of the attribute"} :string]
   [:created_at {:description "The date and time the document metadata was created"} inst?]
   [:updated_at {:description "The date and time the document metadata was updated"} inst?]])

but this doesn't

(def DocumentMetadata
  [:map
   [:value_data_type {:description "The data type of the value"} :string]
   [:attribute_definition_id {:description "The UUID of the attribute definition"} :uuid]
   [:attribute_value {:description "The value of the attribute"} :string]
   [:created_at {:description "The date and time the document metadata was created"} :inst]
   [:updated_at {:description "The date and time the document metadata was updated"} :inst]])