class_docstr: A class for representing multivariate polynomial rings. 
docstr: Convert a rational function to ``dtype``. 
docstr_tok: ["Convert","a","rational","function","to","``","dtype","``","."]
code: def from_FractionField(K1, a, K0):
      """Convert a rational function to ``dtype``."""
      if K1.domain == K0:
          return K1.ring.from_list([a])
  
      q, r = K0.numer(a).div(K0.denom(a))
  
      if r.is_zero:
          return K1.from_PolynomialRing(q, K0.field.ring.to_domain())
      else:
          return None
  
imports: from sympy.polys.domains.ring import Ring
  from sympy.polys.domains.compositedomain import CompositeDomain
  from sympy.polys.polyerrors import CoercionFailed, GeneratorsError
  from sympy.utilities import public
label_desc: Use image node_id 25 for calling the PolynomialRing obj's underlying member method code with example usage: obj.from_FractionField(K1, a, K0) and returns: K1, K1, None