Python 3.7 AttributeError: 'str' object has no attribute 'has' - django

Question

Using Python 3.7.3 , PIP 19.3.1 , Django 2.2, I need to check whether an object is string or not and started by using this code:
if not isinstance(math, basestring):
math = latex(math)
return '<script type="math/tex; mode=display">{}</script>'.format(math)
Using 'str' instead of 'basestring' causes the script to output an error:
'str' object has no attribute 'get' error
I then tried the following code
def format_math_display(self, math):
try:
if not isinstance(math, basestring):
math = latex(math)
return '<script type="math/tex; mode=display">{}
</script>'.format(math)
except Exception:
pass
But it also leads to an(other) error:
AttributeError at /
'str' object has no attribute 'has'
Request Method: POST
Request URL: http://127.0.0.1:8000/
Django Version: 2.2.6
Exception Type: AttributeError
Exception Value: 'str' object has no attribute 'has'
Python Executable: C:\Users\Vasundhara\Envs\calculate\Scripts\python.exe
Python Version: 3.7.3
Python Path:
['C:\\wamp64\\www\\Python3Django2\\Calculate',
'C:\\Users\\Vasundhara\\Envs\\calculate\\Scripts\\python37.zip',
'C:\\Users\\Vasundhara\\Envs\\calculate\\DLLs',
'C:\\Users\\Vasundhara\\Envs\\calculate\\lib',
'C:\\Users\\Vasundhara\\Envs\\calculate\\Scripts',
'c:\\users\\vasundhara\\appdata\\local\\programs\\python\\python37\\Lib',
'c:\\users\\vasundhara\\appdata\\local\\programs\\python\\python37\\DLLs',
'C:\\Users\\Vasundhara\\Envs\\calculate',
'C:\\Users\\Vasundhara\\Envs\\calculate\\lib\\site-packages']
Server time: Sat, 26 Oct 2019 04:08:58 +0000
What am I missing here?