Use this script to migrate your spotify library from one account to another

migrate_spotify_library.py

import requests
old_token = ''
new_token = ''

h = {
    'Authorization': 'Bearer ' + old_token
 }

tracks = []
index = 0
while True:
    url = 'https://api.spotify.com/v1/me/tracks?limit=20&offset='+str(index)
    print("url", url)
    r = requests.get(url, headers=h)
    d = r.json()
    if len(d['items']) == 0:
        break
    else:
        tracks = tracks + d['items']
        print("total", len(tracks))

    index += 20
    
h = {
    'Authorization': 'Bearer ' + new_token
}

for track in tracks:
    track_id = track['track']['id']
    url = 'https://api.spotify.com/v1/me/tracks?ids=' + track_id
    requests.put(url, headers=h)
    print(url)