code: def _boundbox(monitor, fx=None, mins=None, maxs=None, **kwds):
      """produce a bounding-box to facilitate interpolation at the given points
  
      Args:
        monitor (monitor): a mystic monitor instance of existing points
        fx (function, default=None): evaluate as ``z = f(x)`` for new ``x``
        mins (list[float], default=None): list of the minima of the bounding box
        maxs (list[float], default=None): list of the maxima of the bounding box
        all (bool, default=True): include initial ``monitor`` points in the return
  
      Returns:
        a mystic monitor instance containing the requested boundbox points
  
      Notes:
        - if ``mins`` is None, then use the minima found in the ``monitor``.
          Similarly for ``maxs``.
      """
      all = kwds["all"] if "all" in kwds else False
  
      import numpy as np
  
      f = (lambda x: np.nan) if fx is None else fx
  
      from mystic.monitors import Monitor  # XXX: copy or not?
  
      mon = (
          Monitor() if monitor is None else monitor[:]
      )  # XXX: what if empty?
      _mon = Monitor()
  
      x = np.array(mon._x)
      # get 'mins'&'maxs' to use for 'axes' to define bounding box
      if len(x):
          mins = x.T.min(axis=-1) if mins is None else np.array(mins)
          # if not hasattr(mins, '__len__'): mins = (mins,)
      else:
          mins = None
      if len(x):
          maxs = x.T.max(axis=-1) if maxs is None else np.array(maxs)
          # if not hasattr(maxs, '__len__'): maxs = (maxs,)
      else:
          maxs = None
  
      # add points at corners of boundbox (don't include existing points)
      if (
          (mins is None)
          or (maxs is None)
          or not mins.shape
          or not maxs.shape
      ):
          # skip bounding box if 'min'&'max' points are already in monitors
          pass
      else:
          r = np.stack(np.meshgrid(*zip(mins, maxs)), -1).reshape(
              -1, len(x.T)
          )
          n = [_mon(i, f(i)) for i in r if not _isin(i, x)]
          del r, n
      del mins, maxs, x
      return mon + _mon if all else _mon
  
imports: from mystic.math import _rbf
label_desc: Use image node_id 2 for calling a global function with example usage: _boundbox(monitor, fx, mins, maxs) and returns: unknown