code: def fahrenheit_to_celsius(x):
      return (x - 32) / 1.8
  
file_path: matplotlib/galleries/examples/subplots_axes_and_figures/secondary_axis.py
imports: import datetime
  import matplotlib.pyplot
  import numpy
  import matplotlib.dates
  from matplotlib.ticker import AutoMinorLocator
label_desc: Use image node_id 9 for calling a global function with example usage: fahrenheit_to_celsius(x) and returns: unknown