def _parse_headers(self, lines):
        # Passed a list of lines that make up the headers for the current msg
        lastheader = ''
        lastvalue = []
        for lineno, line in enumerate(lines):
            # Check for continuation
            if line[0] == ' \t':
                if not lastheader:
                    # The first line of the headers was a continuation.  This
                    # is illegal, so let's note the defect, store the illegal
                    # line, and ignore it for purposes of headers.
                    defect = errors.FirstHeaderLineIsContinuationDefect(line)
                    self._cur.defects.append(defect)
                    continue
                lastvalue.append(line)
                continue
            if lastheader:
                # XXX reconsider the joining of folded lines
                lhdr = EMPTYSTRING.join(lastvalue)[:-1].rstrip('\r\n')
                self._cur[lastheader] = lhdr
                lastheader, lastvalue = '', []
            # Check for envelope header, i.e. unix-from
            if line.startswith('From '):
                if lineno == 0:
                    # Strip off the trailing newline
                    mo = NLCRE_eol.search(line)
                    if mo:
                        line = line[:-len(mo.group(0))]
                    self._cur.set_unixfrom(line)
                    continue
                elif lineno == len(lines) - 1:
                    # Something looking like a unix-from at the end - it's
                    # probably the first line of the body, so push back the
                    # line and stop.
                    self._input.unreadline(line)
                    return
                else:
                    # Weirdly placed unix-from line.  Note this as a defect
                    # and ignore it.
                    defect = errors.MisplacedEnvelopeHeaderDefect(line)
                    self._cur.defects.append(defect)
                    continue
            # Split the line on the colon separating field name from value.
            i = line.find(':')
            if i < 0:
                defect = errors.MalformedHeaderDefect(line)
                self._cur.defects.append(defect)
                continue
            lastheader = line[:i]
            lastvalue = [line[i+1:].lstrip()]
        # Done with all the lines, so handle the last header.
        if lastheader:
            # XXX reconsider the joining of folded lines
            self._cur[lastheader] = EMPTYSTRING.join(lastvalue).rstrip('\r\n')
dataset/ETHPy150Open babble/babble/include/jython/Lib/email/feedparser.py/FeedParser._parse_headers/operator `in` -> `==`