symbol replacer for file content

converter.py

def conv(file: str, new="converted-file.txt", symbol=",", rep=".") -> str:
  """
  Needs: filename
  Optional: filename, symbol to replace, symbol to replace with
  - reads data, replaces a symbol with an other symbol of choice
  - writes new data in file and returns filename
  """
  with open(file, "r") as f:          #open file
    read = f.read()                   #read content
    repl = read.replace(symbol, rep)  #replace symbol
    g = open(new, "w")                #open new file to write result
    g.write(repl)                     #writing
    g.close()
    return new                        #returning filename

#file = conv('data_with_comma.txt', new='better_data.txt')
#arrayy = np.loadtxt(file, skiprows=1)