Real-time forecasts: 1 param, 1 date

Retrieving one field (10 meter U wind here) for all time steps and  for the forecast starting on 1st January 2015:

#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
server = ECMWFDataServer()
server.retrieve({
    "class": "s2",
    "dataset": "s2s",
    "date": "2015-01-01",
    "expver": "prod",
    "levtype": "sfc",
    "origin": "ecmf",
    "param": "165",
    "step": "0/to/768/by/24",
    "stream": "enfo",
    "target": "CHANGEME",
    "time": "00",
    "type": "cf",
})
#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
server = ECMWFDataServer()
server.retrieve({
    "class": "s2",
    "dataset": "s2s",
    "date": "2015-01-01",
    "expver": "prod",
    "levtype": "sfc",
    "origin": "ecmf",
    "param": "165",
    "step": "0/to/768/by/24",
    "stream": "enfo",
    "target": "CHANGEME",
    "time": "00", 
    "number": "1/to/50",
    "type": "pf",
 })
Real-time forecasts: 1 param, series of dates

Retrieving  1 field (10m U wind) for all time steps and for the whole January 2015. 

#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
server = ECMWFDataServer()
server.retrieve({
    "class": "s2",
    "dataset": "s2s",
    "date": "2015-01-01/2015-01-05/2015-01-08/2015-01-12/2015-01-15/2015-01-19/2015-01-22/2015-01-26/2015-01-29",
    "expver": "prod",
    "levtype": "sfc",
    "origin": "ecmf",
    "param": "165",
    "step": "0/to/768/by/24",
    "stream": "enfo",
    "target": "CHANGEME",
    "time": "00",
    "type": "cf",
})
#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
server = ECMWFDataServer()
server.retrieve({
    "class": "s2",
    "dataset": "s2s",
    "date": "2015-01-01/2015-01-05/2015-01-08/2015-01-12/2015-01-15/2015-01-19/2015-01-22/2015-01-26/2015-01-29",
    "expver": "prod",
    "levtype": "sfc",
    "origin": "ecmf",
    "param": "165",
    "step": "0/to/768/by/24",
    "stream": "enfo",
    "target": "CHANGEME",
    "time": "00", 
     "number": "1/to/50",
    "type": "pf",
 })