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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def preparse_iter(self):
 """ Comments can be anywhere. So break apart the Dockerfile into significant lines and any comments that precede them. And if a line is a carryover from the previous via an escaped-newline, bring the directive with it. """

        to_yield = {}
        last_directive = None
        lines_processed = 0
        for line in self.lines_iter():
            if not line:
                continue
            if line.startswith(u'#'):
                comment = line.lstrip('#').strip()
                # Directives have to precede any instructions
                if lines_processed == 1:
                    if comment.startswith(u'escape='):
                        self.escape_char = comment.split(u'=', 1)[1]
                        continue
                to_yield.setdefault('comments', []).append(comment)
            else:
                # last_directive being set means the previous line ended with a
                # newline escape
                if last_directive:
                    directive, payload = last_directive, line
                else:
                    directive, payload = line.split(u' ', 1)
                if line.endswith(self.escape_char):
                    payload = payload.rstrip(self.escape_char)
                    last_directive = directive
                else:
                    last_directive = None
                to_yield['directive'] = directive
                to_yield['payload'] = payload.strip()
                yield to_yield
                to_yield = {}