error while coding of decision tree

hello sir ,

i was working on decision tree model

then i got error while importing subpocess.call

why this line generating error

call(['dot','-T','png','tree.dot','-o','tree.png')]

FileNotFoundError                         Traceback (most recent call last)
<ipython-input-22-c16d9bbff294> in <module>
----> 1 call(['dot','-T','png','tree.dot','-o','tree.png'])

~\anaconda3\lib\subprocess.py in call(timeout, *popenargs, **kwargs)
    338     retcode = call(["ls", "-l"])
    339     """
--> 340     with Popen(*popenargs, **kwargs) as p:
    341         try:
    342             return p.wait(timeout=timeout)

~\anaconda3\lib\subprocess.py in __init__(self, args, bufsize, executable, stdin, stdout, stderr, preexec_fn, close_fds, shell, cwd, env, universal_newlines, startupinfo, creationflags, restore_signals, start_new_session, pass_fds, encoding, errors, text)
    852                             encoding=encoding, errors=errors)
    853 
--> 854             self._execute_child(args, executable, preexec_fn, close_fds,
    855                                 pass_fds, cwd, env,
    856                                 startupinfo, creationflags, shell,

~\anaconda3\lib\subprocess.py in _execute_child(self, args, executable, preexec_fn, close_fds, pass_fds, cwd, env, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, unused_restore_signals, unused_start_new_session)
   1305             # Start the process
   1306             try:
-> 1307                 hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
   1308                                          # no special security
   1309                                          None, None,

FileNotFoundError: [WinError 2] The system cannot find the file specified