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

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
return a |baseimageheader| subclass instance that knows how to parse the headers of the image in *stream* .