def ind(seq):
  """
Returns the integer indices of a Python list where the list values are true.

tindex = Ngl.ind(plist)

plist -- A Python list, tuple, or one-dimensional NumPy array.
  """
  inds = []
  for i in range(len(seq)):
    if (seq[i] != 0):
      inds.append(i)
  return(inds)