<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def to_str(v, encode=None):
 """convert any list, dict, iterable and primitives object to string """

    if isinstance(v, basestring_type):
        return v

    if isinstance(v, dict):
        return to_dict_str(v, encode)

    if isinstance(v, Iterable):
        return to_list_str(v, encode)

    if encode:
        return encode(v)
    else:
        return default_encode(v)