docs: def simple_peakfinder(x, y, delta):
      '''Detect local maxima and minima in a vector
  
      A point is considered a maximum peak if it has the maximal value, and was
      preceded (to the left) by a value lower by `delta`.
  
      Args
      ----
      y: ndarray
          array of values to find local maxima and minima in
      delta: float
          minimum change in `y` since previous peak to be considered new peak.
          It should be positive and it's absolute value taken to ensure this.
      x: ndarray
          corresponding x-axis positions to y array
  
      Returns
      -------
      max_ind: ndarray
          Indices of local maxima
      min_ind: ndarray
          Indices of local minima
  
      Example
      -------
      max_ind, min_ind = simple_peakfinder(x, y, delta)
  
      # get values of `y` at local maxima
      local_max = y[max_ind]
  
      Notes
      -----
      Matlab Author:      Eli Billauer   http://billauer.co.il/peakdet.html
      Python translation: Chris Muktar   https://gist.github.com/endolith/250860
      Python cleanup:     Ryan J. Dillon
      '''
      import numpy
  
      y = numpy.asarray(y)
  
      max_ind = list()
      min_ind = list()
  
      local_min     = numpy.inf
      local_max     = -numpy.inf
      local_min_pos = numpy.nan
      local_max_pos = numpy.nan
  
      lookformax = True
  
      for i in range(len(y)):
  
          if y[i] > local_max:
              local_max = y[i]
              local_max_pos = x[i]
  
          if y[i] < local_min:
              local_min = y[i]
              local_min_pos = x[i]
  
          if lookformax:
              if y[i] < local_max-abs(delta):
                  max_ind.append(local_max_pos)
                  local_min = y[i]
                  local_min_pos = x[i]
                  lookformax = False
          else:
              if y[i] > local_min+abs(delta):
                  min_ind.append(local_min_pos)
                  local_max = y[i]
                  local_max_pos = x[i]
                  lookformax = True
  
      return numpy.array(max_ind), numpy.array(min_ind)