code: def Roszman1(b, x, y=0):
      b = read_params(b)
      pi = 3.141592653589793238462643383279
      model = b[0] - b[1] * x - arctan(b[2] / (x - b[3])) / pi
      return model - y
  
imports: import os
  from numpy import arctan, array, cos, exp, log, sin
  from lmfit import Parameters
label_desc: Use image node_id 22 for calling a global function with example usage: Roszman1(b, x, y) and returns: unknown