class_docstr: Test remove digits.
class_docstr_tok: ["Test","remove","digits","."]
code: def test_replace_tags(self):
      s = pd.Series("Hi @tag, we will replace you")
      s_true = pd.Series("Hi TAG, we will replace you")
  
      self.assertEqual(
          preprocessing.replace_tags(s, symbol="TAG"), s_true
      )
  
imports: import string
  import pytest
  import pandas
  import numpy
  import doctest
  from texthero import preprocessing, stopwords
  from .None import PandasTestCase
  import warnings
label_desc: Use image node_id 36 for calling the TestPreprocessing obj's underlying member method code with example usage: obj.test_replace_tags() without return types