code: def get_lexer_by_name(_alias, **options):
      """Get a lexer by an alias.
  
      Raises ClassNotFound if not found.
      """
      if not _alias:
          raise ClassNotFound("no lexer for alias %r found" % _alias)
  
      # lookup builtin lexers
      for module_name, name, aliases, _, _ in itervalues(LEXERS):
          if _alias.lower() in aliases:
              if name not in _lexer_cache:
                  _load_lexers(module_name)
              return _lexer_cache[name](**options)
      # continue with lexers from setuptools entrypoints
      for cls in find_plugin_lexers():
          if _alias.lower() in cls.aliases:
              return cls(**options)
      raise ClassNotFound("no lexer for alias %r found" % _alias)
  
imports: import re
  import sys
  import types
  import fnmatch
  from os.path import basename
  from pygments.lexers._mapping import LEXERS
  from pygments.modeline import get_filetype_from_buffer
  from pygments.plugin import find_plugin_lexers
  from pygments.util import ClassNotFound, itervalues, guess_decode
label_desc: Use image node_id 6 for calling a global function with example usage: get_lexer_by_name(_alias) and returns: _lexer_cache, cls