django 2.2以上pymsqlエラー問題解決方法

File "C:\Python37\lib\site-packages\django\db\backends\mysql\base.py", line 36, in 
raise ImproperlyConfigured('mysqlclient 1.3.13 or newer is required; you have %s.' % Database.__version__)
django.core.exceptions.ImproperlyConfigured: mysqlclient 1.3.13 or newer is required; you have 0.9.2.

# if version < (1, 3, 13):
#     raise ImproperlyConfigured('mysqlclient 1.3.13 or newer is required;     you have %s.' % Database.__version__)

File "C:\Python37\lib\site-packages\django\db\backends\mysql\operations.py", line 146, in last_executed_query
    query = query.decode(errors='replace')
AttributeError: 'str' object has no attribute 'decode'

  def last_executed_query(self, cursor, sql, params):
      # With MySQLdb, cursor objects have an (undocumented) "_executed"
      # attribute where the exact query sent to the database is saved.
      # See MySQLdb/cursors.py in the source distribution.
      query = getattr(cursor, '_executed', None)
      if query is not None:
          query = query.decode(errors='replace')
      return query

from django.utils.encoding import force_str
def last_executed_query(self, cursor, sql, params):
      # With MySQLdb, cursor objects have an (undocumented) "_executed"
      # attribute where the exact query sent to the database is saved.
      # See MySQLdb/cursors.py in the source distribution.
      # MySQLdb returns string, PyMySQL bytes.
      return force_str(getattr(cursor, '_executed', None), errors='replace')