The type of a mailbox variable. Mailbox variables are used to communicate values between threads in a synchronous way. The type parameter specifies the type of the value propagated from put to take.

create v creates a new mailbox variable containing value v.

create () creates a new empty mailbox variable.

put mvar value puts a value into a mailbox variable. This value will remain in the mailbox until take is called to remove it. If the mailbox is not empty, the current thread will block until it is emptied.

take mvar will take any currently available value from the mailbox variable. If no value is currently available, the current thread will block, awaiting a value to be put by another thread.

take_available mvar immediately takes the value from mvar without blocking, returning None if the mailbox is empty.

• since 3.2.0

is_empty mvar indicates if put mvar can be called without blocking.

• since 3.2.0