TypeError: first argument must be an iterable of pandas objects, you passed an object of type "Series" pandas에서 series 잘못 연결할 경우에 나는 에러 TypeError Traceback (most recent call last) in ----> 1 pd.concat(s1, s5) 2 frames /usr/local/lib/python3.8/dist-packages/pandas/core/reshape/concat.py in __init__(self, objs, axis, join, keys, levels, names, ignore_index, verify_integrity, copy, sort) 327 ): 328..