code: def mpf_sub(s, t, prec=0, rnd=round_fast):
      """Return the difference of two raw mpfs, s-t. This function is
      simply a wrapper of mpf_add that changes the sign of t."""
      return mpf_add(s, t, prec, rnd, 1)
  
imports: import math
  from bisect import bisect
  import sys
  from .backend import MPZ, MPZ_TYPE, MPZ_ZERO, MPZ_ONE, MPZ_TWO, MPZ_FIVE, BACKEND, STRICT, HASH_MODULUS, HASH_BITS, gmpy, sage, sage_utils
  from .libintmath import giant_steps, trailtable, bctable, lshift, rshift, bitcount, trailing, sqrt_fixed, numeral, isqrt, isqrt_fast, sqrtrem, bin_to_radix
label_desc: Use image node_id 40 for calling a global function with example usage: mpf_sub(s, t, prec, rnd) and returns: mpf_add