code: def parse_latex(s, strict=False, backend="antlr"):
      r"""Converts the input LaTeX string ``s`` to a SymPy ``Expr``.
  
      Parameters
      ==========
  
      s : str
          The LaTeX string to parse. In Python source containing LaTeX,
          *raw strings* (denoted with ``r"``, like this one) are preferred,
          as LaTeX makes liberal use of the ``\`` character, which would
          trigger escaping in normal Python strings.
      backend : str, optional
          Currently, there are two backends supported: ANTLR, and Lark.
          The default setting is to use the ANTLR backend, which can be
          changed to Lark if preferred.
  
          Use ``backend="antlr"`` for the ANTLR-based parser, and
          ``backend="lark"`` for the Lark-based parser.
  
          The ``backend`` option is case-sensitive, and must be in
          all lowercase.
      strict : bool, optional
          This option is only available with the ANTLR backend.
  
          If True, raise an exception if the string cannot be parsed as
          valid LaTeX. If False, try to recover gracefully from common
          mistakes.
  
      Examples
      ========
  
      >>> from sympy.parsing.latex import parse_latex
      >>> expr = parse_latex(r"\frac {1 + \sqrt {\a}} {\b}")
      >>> expr
      (sqrt(a) + 1)/b
      >>> expr.evalf(4, subs=dict(a=5, b=2))
      1.618
      >>> func = parse_latex(r"\int_1^\alpha \dfrac{\mathrm{d}t}{t}", backend="lark")
      >>> func.evalf(subs={"alpha": 2})
      0.693147180559945
      """
  
      if backend == "antlr":
          _latex = import_module(
              "sympy.parsing.latex._parse_latex_antlr",
              import_kwargs={"fromlist": ["X"]},
          )
  
          if _latex is not None:
              return _latex.parse_latex(s, strict)
      elif backend == "lark":
          return parse_latex_lark(s)
      else:
          raise NotImplementedError(
              f"Using the '{backend}' backend in the LaTeX"
              " parser is not supported."
          )
  
imports: from sympy.external import import_module
  from sympy.utilities.decorator import doctest_depends_on
  from sympy.parsing.latex.lark import LarkLaTeXParser, TransformToSymPyExpr, parse_latex_lark
  from .errors import LaTeXParsingError
label_desc: Use image node_id 1 for calling a global function with example usage: parse_latex(s, strict, backend) and returns: _latex, parse_latex_lark