AddHeader(*, name, value)¶
Adds a header to the received email.
str) – The name of the header to add. Must be between 1 and 50 characters, inclusive, and consist of alphanumeric (a-z, A-Z, 0-9) characters and dashes only.
str) – The value of the header to add. Must be less than 2048 characters, and must not contain newline characters (“r” or “n”).