code: def index_of(arrval, value):
      """Return index of array *at or below* value."""
      if value < min(arrval):
          return 0
      return max(np.where(arrval <= value)[0])
  
imports: import matplotlib.pyplot
  import numpy
  from lmfit.models import ExponentialModel, GaussianModel
label_desc: Use image node_id 1 for calling a global function with example usage: index_of(arrval, value) and returns: max, int