Convert python time datetime string to each other

#Convert datetime to string 
def datetime_toString(dt):
     return dt.strftime( " %Y-%m-%d-%H " )

#Convert string to datetime 
def string_toDatetime(string):
     return datetime.strptime(string, " %Y-%m-%d-%H " )

#Convert the string to timestamp form 
def string_toTimestamp(strTime):
     return time.mktime(string_toDatetime(strTime).timetuple())

#Convert timestamp to string form 
def timestamp_toString(stamp):
     return time.strftime( " %Y-%m-%d-%H " , tiem.localtime(stamp))

#Convert datetime type to timestamp form 
def datetime_toTimestamp(dateTim):
     return time.mktime(dateTim.timetuple())