(A,lenient=_C)
\n        Extract the image metadata by reading\n        the initial part of the PNG file up to\n        the start of the ``IDAT`` chunk.\n        All the chunks that precede the ``IDAT`` chunk are\n        read and either processed for metadata or discarded.\n\n        If the optional `lenient` argument evaluates to `True`,\n        checksum failures will raise warnings rather than exceptions.\n
\n        Extract the image metadata by reading\n        the initial part of the PNG file up to\n        the start of the ``IDAT`` chunk.\n        All the chunks that precede the ``IDAT`` chunk are\n        read and either processed for metadata or discarded.\n\n        If the optional `lenient` argument evaluates to `True`,\n        checksum failures will raise warnings rather than exceptions.\n
\ n Extract the image metadata by reading \ n the initial part of the PNG file up to \ n the start of the IDAT chunk . \ n All the chunks that precede the IDAT chunk are \ n read and either processed for metadata or discarded . \ n \ n If the optional lenient argument evaluates to True \ n checksum failures will raise warnings rather than exceptions . \ n
def preamble(A,lenient=_C):
		'\n        Extract the image metadata by reading\n        the initial part of the PNG file up to\n        the start of the ``IDAT`` chunk.\n        All the chunks that precede the ``IDAT`` chunk are\n        read and either processed for metadata or discarded.\n\n        If the optional `lenient` argument evaluates to `True`,\n        checksum failures will raise warnings rather than exceptions.\n        ';A.validate_signature()
		while _H:
			if not A.atchunk:
				A.atchunk=A._chunk_len_type()
				if A.atchunk is _A:raise FormatError('This PNG file has no IDAT chunks.')
			if A.atchunk[1]==_J:return
			A.process_chunk(lenient=lenient)
def preamble ( A , lenient = _C ) : A . validate_signature ( ) while _H : if not A . atchunk : A . atchunk = A . _chunk_len_type ( ) if A . atchunk is _A : raise FormatError ( 'This PNG file has no IDAT chunks.' ) if A . atchunk [ 1 ] == _J : return A . process_chunk ( lenient = lenient )