code: def _nan_exists(data):
      """True if there is at least one np.nan in the array"""
      nan_xy = matrix.nan_indices(data)
      return len(nan_xy) > 0
  
file_path: impyute/impyute/ops/wrapper.py
imports: from functools import wraps
  import numpy
  from .None import error
  from .None import matrix
  from .None import util
label_desc: Use image node_id 10 for calling a global function with example usage: _nan_exists(data) and returns: unknown