class_docstr: Lexer for HTTP sessions.
  
  .. versionadded:: 1.5
code: def header_callback(self, match):
      if match.group(1).lower() == "content-type":
          content_type = match.group(5).strip()
          if ";" in content_type:
              content_type = content_type[
                  : content_type.find(";")
              ].strip()
          self.content_type = content_type
      yield match.start(1), Name.Attribute, match.group(1)
      yield match.start(2), Text, match.group(2)
      yield match.start(3), Operator, match.group(3)
      yield match.start(4), Text, match.group(4)
      yield match.start(5), Literal, match.group(5)
      yield match.start(6), Text, match.group(6)
  
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 2 for calling the HttpLexer obj's underlying member method code with example usage: obj.header_callback(match) without return types