code: def _read_string(f):
      """Read a string"""
      length = _read_long(f)
      if length > 0:
          chars = _read_bytes(f, length).decode("latin1")
          _align_32(f)
      else:
          chars = ""
      return chars
  
imports: import struct
  import numpy
  import tempfile
  import zlib
  import warnings
label_desc: Use image node_id 14 for calling a global function with example usage: _read_string(f) and returns: chars