class_docstr: Represents a field domain. 
class_docstr_tok: ["Represents","a","field","domain","."]
docstr: Returns ``a**(-1)`` if possible. 
docstr_tok: ["Returns","``","a","*","*","(","-1",")","``","if","possible","."]
code: def revert(self, a):
      """Returns ``a**(-1)`` if possible."""
      if a:
          return 1 / a
      else:
          raise NotReversible("zero is not reversible")
  
file_path: sympy/sympy/polys/domains/field.py
imports: from sympy.polys.domains.ring import Ring
  from sympy.polys.polyerrors import NotReversible, DomainError
  from sympy.utilities import public
label_desc: Use image node_id 9 for calling the Field obj's underlying member method code with example usage: obj.revert(a) and returns: unknown