<human>:  first of month for date.
<bot>: Here is a Python function to find the first of month for date

import datetime

def first_of_month(date):
 """Returns the first day of the month for the given date."""
 return date.strftime("%Y-%m-01")

# Enter the date
date = datetime.date(2019, 1, 1)

# Calling the function
print((first_of_month(date)))

#Example Output
# 2019-01-01

#Remember to inspect code for bugs.