docs: def preprocess_bel_stmt(stmt: str) -> str:
      """Clean up basic formatting of BEL statement
  
      Args:
          stmt: BEL statement as single string
  
      Returns:
          cleaned BEL statement
      """
  
      stmt = stmt.strip()  # remove newline at end of stmt
      stmt = re.sub(r",+", ",", stmt)  # remove multiple commas
      stmt = re.sub(r",", ", ", stmt)  # add space after each comma
      stmt = re.sub(r" +", " ", stmt)  # remove multiple spaces
  
      return stmt