class_docstr: A class for representing multivariate rational function fields. 
code: def __str__(self):
      return (
          str(self.domain)
          + "("
          + ",".join(map(str, self.symbols))
          + ")"
      )
  
imports: from sympy.polys.domains.compositedomain import CompositeDomain
  from sympy.polys.domains.field import Field
  from sympy.polys.polyerrors import CoercionFailed, GeneratorsError
  from sympy.utilities import public
label_desc: Use image node_id 6 for calling the FractionField obj's underlying member method code with example usage: obj.__str__() and returns: unknown