def date_struct(year, month, day, tz = "<STR_LIT>"):
ymdtz = (year, month, day, tz)<EOL>if None in ymdtz:<EOL><INDENT>return None <EOL><DEDENT>try:<EOL><INDENT>return time.strptime("<STR_LIT>" % ymdtz,  "<STR_LIT>")<EOL><DEDENT>except(TypeError, ValueError):<EOL><INDENT>pass<EOL><DEDENT>
Given year, month and day numeric values and a timezone
convert to structured date object