code: def clean_tickers(tickers):
      """
      Maps clean_ticker over tickers.
      """
      return [clean_ticker(x) for x in tickers]
  
file_path: ffn/ffn/utils.py
imports: import re
  import decorator
  import numpy
  import pandas
label_desc: Use image node_id 5 for calling a global function with example usage: clean_tickers(tickers) and returns: unknown