def convert_cluster_dict_keys_to_aliases(self, cluster_dict, alias_hash):
output_dict = {}<EOL>directory_to_index_dict = {os.path.split(item["<STR_LIT>"])[<NUM_LIT:0>] : key<EOL>for key, item in alias_hash.iteritems()}<EOL>for key, item in cluster_dict.iteritems():<EOL><INDENT>cluster_file_directory = os.path.split(key)[<NUM_LIT:0>]<EOL>cluster_idx = directory_to_index_dict[cluster_file_directory]<EOL>output_dict[cluster_idx] = item<EOL><DEDENT>return output_dict<EOL>
Parameters
----------
cluster_dict : dict
    dictionary stores information on pre-placement clustering
alias_hash : dict
    Stores information on each input read file given to GraftM, the
    corresponding reads found within each file, and their taxonomy

Returns
--------
updated cluster_dict dict containing alias indexes for keys.