from datetime import timedelta
from marshmallow.fields import Field

class TimeDelta1(Field):
    DAYS = 'days'
    SECONDS = 'seconds'
    MICROSECONDS = 'microseconds'

    def __init__(self, precision='seconds', error=None, **kwargs):
        precision = precision.lower()
        units = (self.DAYS, self.SECONDS, self.MICROSECONDS)

        if precision not in units:
            msg = 'The precision must be "{0}", "{1}" or "{2}".'.format(*units)
            raise ValueError(msg)

        self.precision = precision
        super(TimeDelta1, self).__init__(error=error, **kwargs)

    def _serialize(self, value, attr, obj):
        try:
            days = value.days
            seconds = days * 86400 + value.seconds
            microseconds = seconds * 10**6 + value.microseconds
        except AttributeError:
            msg = '{0!r} cannot be formatted as a timedelta.'.format(value)
            raise MarshallingError(getattr(self, 'error', None) or msg)

        return locals()[self.precision]
    
class TimeDelta2(Field):
    DAYS = 'days'
    SECONDS = 'seconds'
    MICROSECONDS = 'microseconds'

    def __init__(self, precision='seconds', error=None, **kwargs):
        precision = precision.lower()
        units = (self.DAYS, self.SECONDS, self.MICROSECONDS)

        if precision not in units:
            msg = 'The precision must be "{0}", "{1}" or "{2}".'.format(*units)
            raise ValueError(msg)

        self.precision = precision
        super(TimeDelta2, self).__init__(error=error, **kwargs)

    def _serialize(self, value, attr, obj):
        try:
            days = value.days
            if self.precision == self.DAYS:
                return days
            else:
                seconds = days * 86400 + value.seconds
                if self.precision == self.SECONDS:
                    return seconds
                else:  # microseconds
                    return seconds * 10**6 + value.microseconds
        except AttributeError:
            msg = '{0!r} cannot be formatted as a timedelta.'.format()
            raise MarshallingError(getattr(self, 'error', None) or msg)


def seconds1(): 
    f = TimeDelta1(precision='microseconds')
    for i in range(999999):
        obj = {'foo': timedelta(microseconds=i)}
        f.serialize('foo', obj)
    
def seconds2():
    f = TimeDelta2(precision='microseconds')
    for i in range(999999):
        obj = {'foo': timedelta(microseconds=i)}
        f.serialize('foo', obj)



%timeit seconds1()

%timeit seconds2()