def readheaders(self):
        """Read header lines.

        Read header lines up to the entirely blank line that terminates them.
        The (normally blank) line that ends the headers is skipped, but not
        included in the returned list.  If a non-header line ends the headers,
        (which is an error), an attempt is made to backspace over it; it is
        never included in the returned list.

        The variable self.status is set to the empty string if all went well,
        otherwise it is an error message.  The variable self.headers is a
        completely uninterpreted list of lines contained in the header (so
        printing them will reproduce the header exactly as it appears in the
        file).

        If multiple header fields with the same name occur, they are combined
        according to the rules in RFC 2616 sec 4.2:

        Appending each subsequent field-value to the first, each separated
        by a comma. The order in which header fields with the same field-name
        are received is significant to the interpretation of the combined
        field value.
        """
        # XXX The implementation overrides the readheaders() method of
        # rfc822.Message.  The base class design isn't amenable to
        # customized behavior here so the method here is a copy of the
        # base class code with a few small changes.

        self.dict = {}
        self.unixfrom = ''
        self.headers = hlist = []
        self.status = ''
        headerseen = ""
        firstline = 1
        startofline = unread = tell = None
        if hasattr(self.fp, 'unread'):
            unread = self.fp.unread
        elif self.seekable:
            tell = self.fp.tell
        while True:
            if len(hlist) > _MAXHEADERS:
                raise HTTPException(_MAXHEADERS % "got more than %d headers")
            if tell:
                try:
                    startofline = tell()
                except IOError:
                    startofline = tell = None
                    self.seekable = 0
            line = self.fp.readline(_MAXLINE + 1)
            if len(line) > _MAXLINE:
                raise LineTooLong("header line")
            if not line:
                self.status = 'EOF in headers'
                break
            # Skip unix From name time lines
            if firstline and line.startswith('From '):
                self.unixfrom = self.unixfrom + line
                continue
            firstline = 0
            if headerseen and line[0] in ' \t':
                # XXX Not sure if continuation lines are handled properly
                # for http and/or for repeating headers
                # It's a continuation line.
                hlist.append(line)
                self.addcontinue(headerseen, line.strip())
                continue
            elif self.iscomment(line):
                # It's a comment.  Ignore it.
                continue
            elif self.islast(line):
                # Note! No pushback here!  The delimiter line gets eaten.
                break
            headerseen = self.isheader(line)
            if headerseen:
                # It's a legal header line, save it.
                hlist.append(line)
                self.addheader(headerseen, line[len(headerseen)+1:].strip())
                continue
            elif headerseen is not None:
                # An empty header name. These aren't allowed in HTTP, but it's
                # probably a benign mistake. Don't add the header, just keep
                # going.
                continue
            else:
                # It's not a header line; throw it back and stop here.
                if not self.dict:
                    self.status = 'No headers'
                else:
                    self.status = 'Non-header line where header expected'
                # Try to undo the read.
                if unread:
                    unread(line)
                elif tell:
                    self.fp.seek(startofline)
                else:
                    self.status = self.status + '; bad seek'
                break
dataset/ETHPy150Open francelabs/datafari/windows/python/Lib/httplib.py/HTTPMessage.readheaders/swapped operands of `%`