code: def clean_ticker(ticker):
      """
      Cleans a ticker for easier use throughout MoneyTree
  
      Splits by space and only keeps first bit. Also removes
      any characters that are not letters. Returns as lowercase.
  
      >>> clean_ticker('^VIX')
      'vix'
      >>> clean_ticker('SPX Index')
      'spx'
      """
      pattern = re.compile("[\\W_]+")
      res = pattern.sub("", ticker.split(" ")[0])
      return res.lower()
  
file_path: ffn/ffn/utils.py
imports: import re
  import decorator
  import numpy
  import pandas
label_desc: Use image node_id 4 for calling a global function with example usage: clean_ticker(ticker) and returns: res