code: def _has_simple_delta(expr, index):
      """
      Returns True if ``expr`` is an expression that contains a KroneckerDelta
      that is simple in the index ``index``, meaning that this KroneckerDelta
      is nonzero for a single value of the index ``index``.
      """
      if expr.has(KroneckerDelta):
          if _is_simple_delta(expr, index):
              return True
          if expr.is_Add or expr.is_Mul:
              for arg in expr.args:
                  if _has_simple_delta(arg, index):
                      return True
      return False
  
file_path: sympy/sympy/concrete/delta.py
imports: from .products import product
  from .summations import Sum, summation
  from sympy.core import Add, Mul, S, Dummy
  from sympy.core.cache import cacheit
  from sympy.core.sorting import default_sort_key
  from sympy.functions import KroneckerDelta, Piecewise, piecewise_fold
  from sympy.polys.polytools import factor
  from sympy.sets.sets import Interval
  from sympy.solvers.solvers import solve
label_desc: Use image node_id 3 for calling a global function with example usage: _has_simple_delta(expr, index) and returns: False, True, True