【PowerShell】ある年ある月に含まれる日数を取得する

PS > [DateTime]::DaysInMonth(2003, 1)
31
PS > [DateTime]::DaysInMonth(2003, 2)
28
PS > [DateTime]::DaysInMonth(2003, 3)
31
PS > [DateTime]::DaysInMonth(2004, 1)
31
PS > [DateTime]::DaysInMonth(2004, 2)
29
PS > [DateTime]::DaysInMonth(2004, 3)
31