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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 getChildren(self, forgetter, field=None, where=None, orderBy=None):
 """Return the children that links to me. That means that I have to be listed in their _userClasses somehow. If field is specified, that field in my children is used as the pointer to me. Use this if you have multiple fields referring to my class. """

        if type(where) in (types.StringType, types.UnicodeType):
            where = (where,)

        if not field:
            for (i_field, i_class) in forgetter._userClasses.items():
                if isinstance(self, i_class):
                    field = i_field
                    break # first one found is ok :=)
        if not field:
            raise "No field found, check forgetter's _userClasses"
        sqlname = forgetter._sqlFields[field]
        myID = self._getID()[0] # assuming single-primary !

        whereList = ["%s='%s'" % (sqlname, myID)]
        if where:
            whereList.extend(where)
        return forgetter.getAll(whereList, orderBy=orderBy)