code: def bell(ctx, n, x=1):
      x = ctx.convert(x)
      if not n:
          if ctx.isnan(x):
              return x
          return type(x)(1)
      if ctx.isinf(x) or ctx.isinf(n) or ctx.isnan(x) or ctx.isnan(n):
          return x**n
      if n == 1:
          return x
      if n == 2:
          return x * (x + 1)
      if x == 0:
          return ctx.sincpi(n)
      return _polyexp(ctx, n, x, True) / ctx.exp(x)
  
imports: from ..libmp.backend import xrange
  import math
  import cmath
label_desc: Use image node_id 42 for calling a global function with example usage: bell(ctx, n, x) and returns: unknown, type, unknown, x, unknown, ctx, x