Convert the following textual description to an entity$-$relationship diagram in UML notation. Please spend time differentiating between entities, attributes, relationships and values of attributes. If you are identifying a strong entity $-$ make sure you identify a primary key for it$.$ You are not required to use superclass$/$subclass hierarchy for any of these problems, but may choose to do so if you wish. Remember, weak entities do not have a primary key. You are not required to use superclass$/$subclass hierarchy for any of these problems, but may choose to do so if you wish.

A laptop has a unique serial number and is associated with a specific manufacturer and a model for that manufacturer. Each laptop is associated with exactly $1$ manufacturer and $1$ model for that manufacturer. A manufacturer has a unique name. A manufacturer can produce $1$ to many laptop models. A model name is unique for a specific manufacturer but is not unique across all manufacturers. A model name is associated with at least $1$ manufacturer.