Traceback (most recent call last):
  File "electrum\json_db.py", line 321, in put
  File "json\__init__.py", line 238, in dumps
  File "json\encoder.py", line 199, in encode
  File "json\encoder.py", line 257, in iterencode
MemoryError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "electrum\gui\qt\main_window.py", line 155, in request_password
  File "electrum\gui\qt\main_window.py", line 2485, in do_import_privkey
  File "electrum\gui\qt\main_window.py", line 2457, in _do_import
  File "electrum\gui\qt\main_window.py", line 2485, in <lambda>
  File "electrum\wallet.py", line 3473, in import_private_keys
  File "electrum\wallet.py", line 3326, in save_keystore
  File "electrum\json_db.py", line 42, in wrapper
  File "electrum\json_db.py", line 323, in put
MemoryError