Hi, I am setting up ARTIQ 5 using nix. I have been following the manual step by step and have been fine. I am now trying to run the led.py program but when I do artiq_run I get the error message.
`[nix-shell:_/artiq]$ artiq_run led.py
Traceback (most recent call last):
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/master/worker_db.py", line 78, in get
desc = self.get_desc(name)
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/master/worker_db.py", line 69, in get_desc
return self.ddb.get(name, resolve_alias=True)
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/master/databases.py", line 29, in get
desc = self.data.raw_view[key]
KeyError: 'led'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/nix/store/5ydzc5dpa5if9ds671fhr4vk0d695cbk-python3.7-artiq-5.7101.8ca1fea1/bin/.artiq_run-wrapped", line 11, in <module>
sys.exit(main())
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/frontend/artiq_run.py", line 225, in main
return run(with_file=True)
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/frontend/artiq_run.py", line 211, in run
raise exn
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/frontend/artiq_run.py", line 202, in run
exp_inst = _build_experiment(device_mgr, dataset_mgr, args)
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/frontend/artiq_run.py", line 188, in _build_experiment
return get_experiment(module, args.class_name)(managers)
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/language/environment.py", line 220, in init
self.build(*args, **kwargs)
File "led.py", line 7, in build
self.setattr_device("led")
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/language/environment.py", line 304, in setattr_device
setattr(self, key, self.get_device(key))
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/language/environment.py", line 297, in get_device
return self.__device_mgr.get(key)
File "/nix/store/7d5jllypjvlw43bd6hrhlwbv7lfiy7fh-python3-3.7.5-env/lib/python3.7/site-packages/artiq/master/worker_db.py", line 81, in get
.format(name)) from e
artiq.master.worker_db.DeviceError: Failed to get description of device 'led'
Here is my device_db.py filecore_addr = "192.168.1.146"

device_db = {
"core": {
"type": "local",
"module": "artiq.coredevice.core",
"class": "Core",
"arguments": {"host": core_addr, "ref_period": 1e-9}
},
"core_log": {
"type": "controller",
"host": "::1",
"port": 1068,
"command": "aqctl_corelog -p {port} --bind {bind} " + core_addr
},
"core_cache": {
"type": "local",
"module": "artiq.coredevice.cache",
"class": "CoreCache"
},
"core_dma": {
"type": "local",
"module": "artiq.coredevice.dma",
"class": "CoreDMA"
},

"i2c_switch0": {
    "type": "local",
    "module": "artiq.coredevice.i2c",
    "class": "PCA9548",
    "arguments": {"address": 0xe0}
},
"i2c_switch1": {
    "type": "local",
    "module": "artiq.coredevice.i2c",
    "class": "PCA9548",
    "arguments": {"address": 0xe2}
},

}

device_db.update({
"ttl" + str(i): {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLInOut" if i < 4 else "TTLOut",
"arguments": {"channel": i},
} for i in range(24)
})

device_db.update({
"spi_sampler0_adc": {
"type": "local",
"module": "artiq.coredevice.spi2",
"class": "SPIMaster",
"arguments": {"channel": 24}
},
"spi_sampler0_pgia": {
"type": "local",
"module": "artiq.coredevice.spi2",
"class": "SPIMaster",
"arguments": {"channel": 25}
},
"spi_sampler0_cnv": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 26},
},
"sampler0": {
"type": "local",
"module": "artiq.coredevice.sampler",
"class": "Sampler",
"arguments": {
"spi_adc_device": "spi_sampler0_adc",
"spi_pgia_device": "spi_sampler0_pgia",
"cnv_device": "spi_sampler0_cnv"
}
}
})

device_db.update({
"spi_urukul0": {
"type": "local",
"module": "artiq.coredevice.spi2",
"class": "SPIMaster",
"arguments": {"channel": 27}
},
"ttl_urukul0_sync": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLClockGen",
"arguments": {"channel": 28, "acc_width": 4}
},
"ttl_urukul0_io_update": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 29}
},
"ttl_urukul0_sw0": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 30}
},
"ttl_urukul0_sw1": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 31}
},
"ttl_urukul0_sw2": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 32}
},
"ttl_urukul0_sw3": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 33}
},
"urukul0_cpld": {
"type": "local",
"module": "artiq.coredevice.urukul",
"class": "CPLD",
"arguments": {
"spi_device": "spi_urukul0",
"io_update_device": "ttl_urukul0_io_update",
"sync_device": "ttl_urukul1_sync",
"refclk": 125e6,
"clk_sel": 2
}
}
})

device_db.update({
"urukul0_ch" + str(i): {
"type": "local",
"module": "artiq.coredevice.ad9910",
"class": "AD9910",
"arguments": {
"pll_n": 32,
"chip_select": 4 + i,
"cpld_device": "urukul0_cpld",
"sw_device": "ttl_urukul0_sw" + str(i)
}
} for i in range(4)
})

device_db.update({
"spi_urukul1": {
"type": "local",
"module": "artiq.coredevice.spi2",
"class": "SPIMaster",
"arguments": {"channel": 34}
},
"ttl_urukul1_sync": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLClockGen",
"arguments": {"channel": 35, "acc_width": 4}
},
"ttl_urukul1_io_update": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 36}
},
"ttl_urukul1_sw0": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 37}
},
"ttl_urukul1_sw1": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 38}
},
"ttl_urukul1_sw2": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 39}
},
"ttl_urukul1_sw3": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 40}
},
"urukul1_cpld": {
"type": "local",
"module": "artiq.coredevice.urukul",
"class": "CPLD",
"arguments": {
"spi_device": "spi_urukul1",
"io_update_device": "ttl_urukul1_io_update",
"refclk": 125e6,
"sync_device": "ttl_urukul1_sync",
"clk_sel": 2
}
}
})

device_db.update({
"urukul1_ch" + str(i): {
"type": "local",
"module": "artiq.coredevice.ad9910",
"class": "AD9910",
"arguments": {
"pll_n": 32,
"chip_select": 4 + i,
"cpld_device": "urukul1_cpld",
"sw_device": "ttl_urukul1_sw" + str(i)
}
} for i in range(4)
})

device_db.update({
"spi_zotino0": {
"type": "local",
"module": "artiq.coredevice.spi2",
"class": "SPIMaster",
"arguments": {"channel": 41}
},
"ttl_zotino0_ldac": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 42}
},
"ttl_zotino0_clr": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 43}
},
"zotino0": {
"type": "local",
"module": "artiq.coredevice.zotino",
"class": "Zotino",
"arguments": {
"spi_device": "spi_zotino0",
"ldac_device": "ttl_zotino0_ldac",
"clr_device": "ttl_zotino0_clr"
}
}
})

device_db.update({
"led0": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 44}
},
"led1": {
"type": "local",
"module": "artiq.coredevice.ttl",
"class": "TTLOut",
"arguments": {"channel": 45}
}
}
)
`