code: def ft_r_dep(ft_r, sf_s, sf_t):
      dsf = sf_t - sf_s
      velo = ft_r / dsf
      return velo, dsf
  
imports: import pytest
  import numpy
  import pandas
  from pandas.testing import assert_frame_equal
  from deepgraph import DeepGraph
label_desc: Use image node_id 4 for calling a global function with example usage: ft_r_dep(ft_r, sf_s, sf_t) and returns: velo,  dsf