Unhandled exception (#1ba66afb) #3912

Running version: 1.3.8.22#dev
Python version: 2.7.15
Operating system: Darwin-17.7.0-x86_64-i386-64bit
Command line: /usr/local/bin/sqlmap -u ************************************************************************************** --level 2 --random-agent --os-shell
Technique: UNION
Back-end DBMS: PostgreSQL (fingerprinted)

Traceback (most recent call last):
  File "sqlmap", line 180, in main
    start()
  File "/Users/******/RD/tools/python/sqlmap/lib/core/decorators.py", line 75, in _
    result = f(*args, **kwargs)
  File "/Users/******/RD/tools/python/sqlmap/lib/controller/controller.py", line 692, in start
    action()
  File "/Users/******/RD/tools/python/sqlmap/lib/controller/action.py", line 216, in action
    conf.dbmsHandler.osShell()
  File "/Users/******/RD/tools/python/sqlmap/plugins/generic/takeover.py", line 84, in osShell
    self.shell()
  File "/Users/******/RD/tools/python/sqlmap/lib/takeover/abstraction.py", line 161, in shell
    self.runCmd(command)
  File "/Users/******/RD/tools/python/sqlmap/lib/takeover/abstraction.py", line 97, in runCmd
    output = self.evalCmd(cmd)
  File "/Users/******/RD/tools/python/sqlmap/lib/takeover/abstraction.py", line 68, in evalCmd
    retVal = self.copyExecCmd(cmd)
  File "/Users/******/RD/tools/python/sqlmap/plugins/dbms/postgresql/takeover.py", line 107, in copyExecCmd
    output = os.linesep.join(output)
TypeError: sequence item 0: expected string, list found