class_docstr: For Notmuch email text format.
  
  .. versionadded:: 2.5
  
  Additional options accepted:
  
  `body_lexer`
      If given, highlight the contents of the message body with the specified
      lexer, else guess it according to the body content (default: ``None``).
code: def __init__(self, **options):
      self.body_lexer = options.get("body_lexer", None)
      RegexLexer.__init__(self, **options)
  
imports: import re
  from pygments.lexers import guess_lexer, get_lexer_by_name
  from pygments.lexer import RegexLexer, bygroups, default, include
  from pygments.token import Text, Comment, Operator, Keyword, Name, String, Number, Generic, Literal, Punctuation
  from pygments.util import ClassNotFound
label_desc: Use image node_id 3 to create a new NotmuchLexer object from inherited base classes: RegexLexer with example: obj = NotmuchLexer()