class_docstr: Represents a field domain. 
class_docstr_tok: ["Represents","a","field","domain","."]
docstr: Return true if ``a`` is a invertible
docstr_tok: ["Return","true","if","``","a","``","is","a","invertible"]
code: def is_unit(self, a):
      """Return true if ``a`` is a invertible"""
      return bool(a)
  
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 10 for calling the Field obj's underlying member method code with example usage: obj.is_unit(a) and returns: bool