Dictionary key/values being seperated onto new lines in complex dictionary?

I am using:

```
yapf 0.28.0
```

I have a dictionary that looks like this

```
query = {
'start': '1m-ago',
'queries': [
{
'metric': 'value.%d' % variable_id,
'aggregator': 'sum',
'downsample': '1d-avg',
'filters': [
{
'tagk': 'valid_id',
'filter': valid_id,
'type': 'literal_or',
'groupBy': False,
},
],
'rate': True,
'rateOptions': {
'counter': 'true',
'resetValue': 1000000000000
}
},
]
}
```

When I run yapf, I get a reformated dictionary that looks like this:

```
query = {
'start':
'1m-ago',
'queries': [
{
'metric':
'value.%d' % variable_id,
'aggregator':
'sum',
'downsample':
'1d-avg',
'filters': [
{
'tagk': 'valid_id',
'filter': valid_id,
'type': 'literal_or',
'groupBy': False,
},
],
'rate':
True,
'rateOptions': {
'counter': 'true',
'resetValue': 1000000000000
}
},
]
}
```

---

Why are some of my key/values being separated into two lines? Not all of them are separated and the ones that are, are some of the shorter lines.