class type mime_header =object..end
Netmime.mime_header_ro    Supports all these read access method, toomethod ro : boolmethod set_fields : (string * string) list -> unitmethod update_field : string -> string -> unitmethod update_multiple_field : string -> string list -> unitmethod delete_field : string -> unitImmutable will be raised.
 set_fields replaces the current fields with a new list of
 (name,value) pairs. update_field name value replaces all fields
 of the passed name with the single setting (name,value), or
 adds this setting to the list. update_multiple_field name values
 replaces all fields of the passed name with the list of values,
 or adds this list. Finally, delete_field name deletes all
 fields of the passed name. Nothing happens if there is no such
 field.
 Both update_field and update_multiple_field first replace
 existing values by the new ones without changing the order
 of the fields in the header. Additional values are inserted
 after the last existing value, or at the end of the header.