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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 apply(self, aliases):
 """Apply the merge to the routing table it is defined against and get a new routing table and alias dictionary. Returns ------- A new routing table which may be minimised further. A new aliases dictionary. """

        # Create a new routing table of the correct size
        new_size = len(self.routing_table) - len(self.entries) + 1
        new_table = [None for _ in range(new_size)]

        # Create a copy of the aliases dictionary
        aliases = dict(aliases)

        # Get the new entry
        new_entry = RoutingTableEntry(
            route=self.routing_table[next(iter(self.entries))].route,
            key=self.key, mask=self.mask, sources=self.sources
        )
        aliases[(self.key, self.mask)] = our_aliases = set([])

        # Iterate through the old table copying entries acrosss
        insert = 0
        for i, entry in enumerate(self.routing_table):
            # If this is the insertion point then insert
            if i == self.insertion_index:
                new_table[insert] = new_entry
                insert += 1

            if i not in self.entries:
                # If this entry isn't to be removed then copy it across to the
                # new table.
                new_table[insert] = entry
                insert += 1
            else:
                # If this entry is to be removed then add it to the aliases
                # dictionary.
                km = (entry.key, entry.mask)
                our_aliases.update(aliases.pop(km, {km}))

        # If inserting beyond the end of the old table then insert at the end
        # of the new table.
        if self.insertion_index == len(self.routing_table):
            new_table[insert] = new_entry

        return new_table, aliases