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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 minimise(table, target_length, check_for_aliases=True):
 """Remove from the routing table any entries which could be replaced by default routing. Parameters Routing table from which to remove entries which could be handled by default routing. target_length : int or None Target length of the routing table. check_for_aliases : bool If True (the default), default-route candidates are checked for aliased entries before suggesting a route may be default routed. This check is required to ensure correctness in the general case but has a runtime complexity of O(N^2) in the worst case for N-entry tables. If False, the alias-check is skipped resulting in O(N) runtime. This option should only be used if the supplied table is guaranteed not to contain any aliased entries. Raises ------ MinimisationFailedError If the smallest table that can be produced is larger than `target_length`. Returns ------- Reduced routing table entries. """

    # If alias checking is required, see if we can cheaply prove that no
    # aliases exist in the table to skip this costly check.
    if check_for_aliases:
        # Aliases cannot exist when all entries share the same mask and all
        # keys are unique.
        if len(set(e.mask for e in table)) == 1 and \
                len(table) == len(set(e.key for e in table)):
            check_for_aliases = False

    # Generate a new table with default-route entries removed
    new_table = list()
    for i, entry in enumerate(table):
        if not _is_defaultable(i, entry, table, check_for_aliases):
            # If the entry cannot be removed then add it to the table
            new_table.append(entry)

    # If the resultant table is larger than the target raise an exception
    if target_length is not None and target_length < len(new_table):
        raise MinimisationFailedError(target_length, len(new_table))

    return new_table