class_docstr: Mathematics domain.
code: def get_equation_number_for(self, labelid: str) -> int | None:
      if labelid in self.equations:
          return self.equations[labelid][1]
      else:
          return None
  
imports: from __future__ import annotations
  from typing import TYPE_CHECKING, Any
  from docutils import nodes
  from docutils.nodes import Element, Node, make_id, system_message
  from sphinx.domains import Domain
  from sphinx.locale import __
  from sphinx.roles import XRefRole
  from sphinx.util import logging
  from sphinx.util.nodes import make_refnode
label_desc: Use image node_id 3 for calling the MathDomain obj's underlying member method code with example usage: obj.get_equation_number_for(labelid) and returns: self, None