class_docstr: Pack various data representations into a buffer.
class_docstr_tok: ["Pack","various","data","representations","into","a","buffer","."]
code: def pack_fstring(self, n, s):
      if n < 0:
          raise ValueError("fstring size must be nonnegative")
      data = s[:n]
      n = ((n + 3) // 4) * 4
      data = data + (n - len(data)) * b"\0"
      self.__buf.write(data)
  
imports: import struct
  from io import BytesIO
  from functools import wraps
  import warnings
label_desc: Use image node_id 10 for calling the Packer obj's underlying member method code with example usage: obj.pack_fstring(n, s) without return types