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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 get_binfo(self):
 """ Fetch a node's build information. node - the node whose sources will be collected cache - alternate node to use for the signature cache returns - the build signature This no longer handles the recursive descent of the node's children's signatures. We expect that they're already built and updated by someone else, if that's what's wanted. """

        try:
            return self.binfo
        except AttributeError:
            pass

        binfo = self.new_binfo()
        self.binfo = binfo

        executor = self.get_executor()
        ignore_set = self.ignore_set

        if self.has_builder():
            binfo.bact = str(executor)
            binfo.bactsig = SCons.Util.MD5signature(executor.get_contents())

        if self._specific_sources:
            sources = [ s for s in self.sources if not s in ignore_set]

        else:
            sources = executor.get_unignored_sources(self, self.ignore)

        seen = set()
        binfo.bsources = [s for s in sources if s not in seen and not seen.add(s)]
        binfo.bsourcesigs = [s.get_ninfo() for s in binfo.bsources]


        binfo.bdepends = self.depends
        binfo.bdependsigs = [d.get_ninfo() for d in self.depends if d not in ignore_set]

        binfo.bimplicit = self.implicit or []
        binfo.bimplicitsigs = [i.get_ninfo() for i in binfo.bimplicit if i not in ignore_set]


        return binfo