presto - timestamps and decimal(38,18) returned as strings? #290

Why are presto timestamp/decimal(38,18) data types returned a string (enclosed in u'') instead of python datetime/numeric types?

#presto jdbc:
select typeof(col1),typeof(col2),typeof(col3),typeof(col4),typeof(col5),typeof(col6) from hive.x.y
#result is
timestamp timestamp bigint decimal(38,18) varchar varchar

desc hive.x.y
#result is
for_dt timestamp NO NO NO NO 1
for_d timestamp NO NO NO NO 2
for_h bigint NO NO NO NO 3
value decimal(38,18) NO NO NO NO 4
metric varchar(2147483647) NO NO NO NO 5
lat_lon varchar(2147483647) NO NO NO NO 6

attempt 1
#python
from sqlalchemy.engine import create_engine
engine = create_engine('presto://u:p@host:port',connect_args={'protocol': 'https', 'requests_kwargs': {'verify': 'mypem'}})
result = engine.execute('select * from hive.x.y limit 1')
print(result.fetchall())
#result is
[(u'2010-02-18 03:00:00.000', u'2010-02-18 00:00:00.000', 3, u'-0.191912651062011660', u'hey', u'there')]

attempt 2
#python
from pyhive import presto
import requests
from requests.auth import HTTPBasicAuth

req_kw = {
'verify': 'mypem',
'auth': HTTPBasicAuth('u', 'p')
}

cursor = presto.connect(
host='host',
port=port,
protocol='https',
username='u',
requests_kwargs=req_kw,
).cursor()

query = '''select * from x.y limit 1'''
cursor.execute(query)
print cursor.fetchall()
#result is
[(u'2010-02-18 03:00:00.000', u'2010-02-18 00:00:00.000', 3, u'-0.191912651062011660', u'hey', u'there')]