code: def replace_in_file(filename, oldvalue, newvalue):
      """Replace string in a file and optionally create backup_filename."""
      # Read in the file
      with open(filename, "r") as f:
          filedata = f.read()
  
      # Replace the target string
      filedata = filedata.replace(oldvalue, newvalue)
  
      # Write the file out again
      with open(filename, "w") as f:
          f.write(filedata)
  
imports: import streamlit
  import os
  from dotenv import load_dotenv
label_desc: Use image node_id 1 for calling a global function with example usage: replace_in_file(filename, oldvalue, newvalue) without return types