code: def inst_def(self) -> InstDef | None:
      if hdr := self.inst_header():
          if block := self.block():
              return InstDef(
                  hdr.annotations,
                  hdr.kind,
                  hdr.name,
                  hdr.inputs,
                  hdr.outputs,
                  block,
              )
          raise self.make_syntax_error("Expected block")
      return None
  
imports: from dataclasses import dataclass, field
  from typing import NamedTuple, Callable, TypeVar, Literal, cast
  import lexer
  from plexer import PLexer
label_desc: Use image node_id 2 for calling the Parser obj's underlying member method code with example usage: obj.inst_def() and returns: None, InstDef