Handle Nan when using Pandas ExcelWriter in python
<p>How would I change the following code to handle NaN values as just empty cells within my dataframe as I iterate through it line by line outputting values in column A?</p>

<pre><code>excel = pd.ExcelWriter(f_name,engine='xlsxwriter')
wb = excel.book
ws = wb.add_worksheet('PnL')

for i in len(df):
  ws.write(0,i,df.iloc[i]['A'])
</code></pre>