<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def get_morph_files(directory):
    '''Get a list of all morphology files in a directory

    Returns:
        list with all files with extensions '.swc' , 'h5' or '.asc' (case insensitive)
    '''
    lsdir = (os.path.join(directory, m) for m in os.listdir(directory))
    return list(filter(_is_morphology_file, lsdir))