def _get_explicit_connections(self):
        """
        Returns
        -------
        dict
            Explicit connections in this `Group`, represented as a mapping
            from the pathname of the target to the pathname of the source.
        """
        connections = {}
        for sub in self.subgroups():
            connections.update(sub._get_explicit_connections())

        to_abs_uname = self._sysdata.to_abs_uname
        to_abs_pnames = self._sysdata.to_abs_pnames

        for tgt, srcs in iteritems(self._src):
            for src, idxs in srcs:
                try:
                    src_pathnames = [to_abs_uname[src]]
                except __HOLE__ as error:
                    try:
                        src_pathnames = to_abs_pnames[src]
                    except KeyError as error:
                        raise NameError("Source '%s' cannot be connected to "
                                        "target '%s': '%s' does not exist." %
                                        (src, tgt, src))
                try:
                    for tgt_pathname in to_abs_pnames[tgt]:
                        for src_pathname in src_pathnames:
                            connections.setdefault(tgt_pathname,
                                                   []).append((src_pathname,
                                                               idxs))
                except KeyError as error:
                    try:
                        to_abs_uname[tgt]
                    except KeyError as error:
                        raise NameError("Source '%s' cannot be connected to "
                                        "target '%s': '%s' does not exist." %
                                        (src, tgt, tgt))
                    else:
                        raise NameError("Source '%s' cannot be connected to "
                                        "target '%s': Target must be a "
                                        "parameter but '%s' is an unknown." %
                                        (src, tgt, tgt))

        return connections
dataset/ETHPy150Open OpenMDAO/OpenMDAO/openmdao/core/group.py/Group._get_explicit_connections