code: def streq(a, b):
      return str(a) == str(b)
  
file_path: sympy/sympy/physics/optics/tests/test_gaussopt.py
imports: from sympy.core.evalf import N
  from sympy.core.numbers import Float, I, oo, pi
  from sympy.core.symbol import symbols
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.functions.elementary.trigonometric import atan2
  from sympy.matrices.dense import Matrix
  from sympy.polys.polytools import factor
  from sympy.physics.optics import BeamParameter, CurvedMirror, CurvedRefraction, FlatMirror, FlatRefraction, FreeSpace, GeometricRay, RayTransferMatrix, ThinLens, conjugate_gauss_beams, gaussian_conj, geometric_conj_ab, geometric_conj_af, geometric_conj_bf, rayleigh2waist, waist2rayleigh
label_desc: Use image node_id 1 for calling a global function with example usage: streq(a, b) and returns: unknown