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7.3.2.3 `MHMessage`

class `MHMessage`( | [message])

  A message with MH-specific behaviors. Parameter message has the same meaning as with the `Message` constructor.

MH messages do not support marks or flags in the traditional sense, but they do support sequences, which are logical groupings of arbitrary messages. Some mail reading programs (although not the standard mh and nmh) use sequences in much the same way flags are used with other formats, as follows:

Sequence | Explanation
--- | ---
unseen | Not read, but previously detected by MUA
replied | Replied to
flagged | Marked as important

`MHMessage` instances offer the following methods:

`get_sequences`( | )

  Return a list of the names of sequences that include this message.

`set_sequences`( | sequences)

  Set the list of sequences that include this message.

`add_sequence`( | sequence)

  Add sequence to the list of sequences that include this message.

`remove_sequence`( | sequence)

  Remove sequence from the list of sequences that include this message.

When an `MHMessage` instance is created based upon a `MaildirMessage` instance, the following conversions take place:

Resulting state | `MaildirMessage` state
--- | ---
"unseen" sequence | no S flag
"replied" sequence | R flag
"flagged" sequence | F flag

When an `MHMessage` instance is created based upon an `mboxMessage` or `MMDFMessage` instance, the Status: and X-Status: headers are omitted and the following conversions take place:

Resulting state | `mboxMessage` or `MMDFMessage` state
--- | ---
"unseen" sequence | no R flag
"replied" sequence | A flag
"flagged" sequence | F flag

When an `MHMessage` instance is created based upon a `BabylMessage` instance, the following conversions take place:

Resulting state | `BabylMessage` state
--- | ---
"unseen" sequence | "unseen" label
"replied" sequence | "answered" label