lazy_map is a blatant copy of the pyrsistent.pmap function, and is used to create lazy maps.

def lazy_map(initial={}, pre_size=0):
    '''
    lazy_map is a blatant copy of the pyrsistent.pmap function, and is used to create lazy maps.
    '''
    if is_lazy_map(initial): return initial
    if not initial: return _EMPTY_LMAP
    return _lazy_turbo_mapping(initial, pre_size)