class_docstr: Context for fast low-precision arithmetic (53-bit precision, giving at most
  about 15-digit accuracy), using Python's builtin float and complex.
code: def bernoulli(ctx, n):
      cache = ctx._bernoulli_cache
      if n in cache:
          return cache[n]
      cache[n] = to_float(mpf_bernoulli(n, 53, "n"), strict=True)
      return cache[n]
  
imports: from .ctx_base import StandardBaseContext
  import math
  import cmath
  from .None import math2
  from .None import function_docs
  from .libmp import mpf_bernoulli, to_float, int_types
  from .None import libmp
label_desc: Use image node_id 7 for calling the FPContext obj's underlying member method code with example usage: obj.bernoulli(ctx, n) and returns: cache, cache