code: def expr_from_dict(rep, *gens):
      """Convert a multinomial form into an expression."""
      result = []
  
      for monom, coeff in rep.items():
          term = [coeff]
          for g, m in zip(gens, monom):
              if m:
                  term.append(Pow(g, m))
  
          result.append(Mul(*term))
  
      return Add(*result)
  
imports: from __future__ import annotations
  from sympy.external.gmpy import GROUND_TYPES
  from sympy.core import S, Add, Mul, Pow, Eq, Expr, expand_mul, expand_multinomial
  from sympy.core.exprtools import decompose_power, decompose_power_rat
  from sympy.core.numbers import _illegal
  from sympy.polys.polyerrors import PolynomialError, GeneratorsError
  from sympy.polys.polyoptions import build_options
  import re
label_desc: Use image node_id 15 for calling a global function with example usage: expr_from_dict(rep) and returns: Add