code: def parallel_func(func, n_jobs, verbose=5):
      """Return parallel instance with delayed function
  
      Util function to use joblib only if available
  
      Parameters
      ----------
      func : callable
          A function
      n_jobs : int
          Number of jobs to run in parallel
      verbose : int
          Verbosity level
  
      Returns
      -------
      parallel : instance of joblib.Parallel or list
          The parallel object
      my_func : callable
          func if not parallel or delayed(func)
      n_jobs : int
          Number of jobs >= 0
  
      Examples
      --------
      >>> from math import sqrt
      >>> from statsmodels.tools.parallel import parallel_func
      >>> parallel, p_func, n_jobs = parallel_func(sqrt, n_jobs=-1, verbose=0)
      >>> print(n_jobs)
      >>> parallel(p_func(i**2) for i in range(10))
      """
      try:
          try:
              from joblib import Parallel, delayed
          except ImportError:
              from sklearn.externals.joblib import Parallel, delayed
  
          parallel = Parallel(n_jobs, verbose=verbose)
          my_func = delayed(func)
  
          if n_jobs == -1:
              try:
                  import multiprocessing
  
                  n_jobs = multiprocessing.cpu_count()
              except (ImportError, NotImplementedError):
                  import warnings
  
                  warnings.warn(
                      module_unavailable_doc.format("multiprocessing"),
                      ModuleUnavailableWarning,
                  )
                  n_jobs = 1
  
      except ImportError:
          import warnings
  
          warnings.warn(
              module_unavailable_doc.format("joblib"),
              ModuleUnavailableWarning,
          )
          n_jobs = 1
          my_func = func
          parallel = list
      return parallel, my_func, n_jobs
  
label_desc: Use image node_id 1 for calling a global function with example usage: parallel_func(func, n_jobs, verbose) and returns: parallel,  my_func,  n_jobs