code: def _cov_1d(x):
      x = x - x.mean()
      ddof = x.shape[0] - 1
      return np.dot(x.T, x.conj()) / ddof
  
imports: import functools
  import importlib
  import importlib.resources
  import re
  import warnings
  from functools import lru_cache
  import matplotlib.pyplot
  import numpy
  from numpy import newaxis
  from .rcparams import rcParams
label_desc: Use image node_id 14 for calling a global function with example usage: _cov_1d(x) and returns: unknown