filling missing data with nan in a data according to the date and time array

insert nan values for missing data in a time series measurement

the code helps to fill in the gaps in a time series data. for this, it requires a DateTime array with missing dates and time and the measurement array with a corresponding missing value. it will check the dates that are missing in the date array and fill in Nan for the corresponding date in the measured array which will help in getting a continuous time series data