code: def _ImageHeaderFactory(stream):
      
      from docx.image import SIGNATURES
  
      def read_32(stream):
          stream.seek(0)
          return stream.read(32)
  
      header = read_32(stream)
      for cls, offset, signature_bytes in SIGNATURES:
          end = offset + len(signature_bytes)
          found_bytes = header[offset:end]
          if found_bytes == signature_bytes:
              return cls.from_stream(stream)
      raise UnrecognizedImageError
docs: Return a |BaseImageHeader| subclass instance that knows how to parse the
      headers of the image in *stream*.