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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 collect(self_or_cls, files, drop=[], metadata=True):
 """ Given a list or NdMapping type containing file paths return a Layout of Collators, which can be called to load a given set of files using the current Importer. If supplied as a list each file is expected to disambiguate itself with contained metadata. If an NdMapping type is supplied additional key dimensions may be supplied as long as they do not clash with the file metadata. Any key dimension may be dropped by name by supplying a drop argument. """

        aslist = not isinstance(files, (NdMapping, Element))
        if isinstance(files, Element):
            files = Collator(files)
            file_kdims = files.kdims
        else:
            file_kdims = files.kdims
        drop_extra = files.drop if isinstance(files, Collator) else []

        mdata_dims = []
        if metadata:
            fnames = [fname[0] if isinstance(fname, tuple) else fname
                      for fname in files.values()]
            mdata_dims = {kdim for fname in fnames
                          for kdim in self_or_cls.key(fname).keys()}
        file_dims = set(files.dimensions('key', label=True))
        added_dims = set(mdata_dims) - file_dims
        overlap_dims = file_dims & set(mdata_dims)
        kwargs = dict(kdims=file_kdims + sorted(added_dims),
                      vdims=['filename', 'entries'],
                      value_transform=self_or_cls.loader,
                      drop=drop_extra + drop)
        layout_data = defaultdict(lambda: Collator(None, **kwargs))

        for key, fname in files.data.items():
            fname = fname[0] if isinstance(fname, tuple) else fname
            mdata = self_or_cls.key(fname) if metadata else {}
            for odim in overlap_dims:
                kval = key[files.get_dimension_index(odim)]
                if kval != mdata[odim]:
                    raise KeyError("Metadata supplies inconsistent "
                                   "value for dimension %s" % odim)
            mkey = tuple(mdata.get(d, None) for d in added_dims)
            key = mkey if aslist else key + mkey
            if isinstance(fname, tuple) and len(fname) == 1:
                (fname,) = fname
            for entry in self_or_cls.entries(fname):
                layout_data[entry][key] = (fname, [entry])
        return Layout(layout_data.items())