class_docstr: A class for representing multivariate polynomial rings. 
docstr: Returns True if `LC(a)` is non-positive. 
docstr_tok: ["Returns","True","if","`","LC","(","a",")","`","is","non-positive","."]
code: def is_nonpositive(self, a):
      """Returns True if `LC(a)` is non-positive."""
      return self.domain.is_nonpositive(a.LC)
  
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 30 for calling the PolynomialRing obj's underlying member method code with example usage: obj.is_nonpositive(a) and returns: self