Indentation in python codes get lost when using package pythonhighlight

I wrote an introduction note about python, which included something like the following

...
\usepackage{pythonhighlight}
...
the following indentation works in python
\begin{python}
a=5
if a==4:
    print(a)
elif a==5:
    print(a-1)
\end{python}
and removing the indentation leads to an error
\begin{python}
a=5
if a==4:
print(a)
elif a==5:
print(a-1)
\end{python}

When I compiled for the first time, the pdf had all the indentations that I wanted.

However, after I completed the note and distributed, I get questions about what I mean here. After check the latex file, I surprisingly found that all the indentation in the latex file get lost. So the above code becomes

...
\usepackage{pythonhighlight}
...
the following indentation works in python
\begin{python}
a=5
if a==4:
print(a)
elif a==5:
print(a-1)
\end{python}
and removing the indentation leads to an error
\begin{python}
a=5
if a==4:
print(a)
elif a==5:
print(a-1)
\end{python}

I, of course, didn't do anything. I am wondering what could be a potential reason for that. Could it be a hotkey combination that I accidentally touched? For your information, I use TeXstudio.