[Clarification] Why is there no volume data in the json response?

* Tiingo Python version: tiingo==0.12.0
* Python version: 3.7.5
* Operating System: Ubuntu 18.04

### Description

I want to download the intraday open, close, high, low, volume data for a stock, but I don't see the volume data.

### What I Did
I ran
```
client.get_dataframe('GOOGL',
frequency='30Min',
startDate='2020-04-19',
endDate='2020-04-22')
```
Here is the output (in the form of json not a pandas dataframe):
```
{'date': '2020-04-21T18:30:00.000Z',
'close': 1215.28,
'high': 1225.98,
'low': 1214.99,
'open': 1225.98}
```
I don't see any volume data in the return. However, when I use the daily command:

```
client.get_ticker_price("GOOGL", frequency="daily")
```

I get the volume data (as well as other additional info different from the intraday data).
```
{"date":"2012-01-10T00:00:00.000Z",
"close":18.72,
"high":19.05,
"low":18.62,
"open":19.01,
"volume":59344400,
"adjClose":14.2957764614,
"adjHigh":14.5477853414,
"adjLow":14.2194101342,
"adjOpen":14.5172388104,
"adjVolume":61684111,
"divCash":0.0,
"splitFactor":1.0}
```

What am I doing wrong?
.. and thanks for a very useful package so far!