Value error while using linear regression | ML
You have missing values in your DF (NaN) means no observations. You need to skip these values since linear regression cannot handle them. Looks like conversion of sqm failed. Check what the format is and try to get int or float from sqm column to avoid NaN.

If you want to skip NaNs read the docs: https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.dropna.html