I tried doing what @junpenglao and @colcarroll pointed to at https://github.com/pymc-devs/pymc3/pull/2975 but I keep getting errors.

My model:

```
with pm.Model() as mG:
alpha = pm.Normal(...)
beta = [...]
sigma = [...]
mu =[...]
Ages = pm.Normal(...)
trace_mG = pm.sample(2000, tune=1000, random_seed=13)
```

Saving trace:

`trace_1 = pm.save_trace(trace_mG)`

Loading trace:

```
with mG:
trace2 = pm.load_trace(trace_1)
```

The error I get:

```
AttributeError Traceback (most recent call last)
<ipython-input-201-ecc0fb6c7706> in <module>()
1 # rr = pm.load_trace('m', model=mG)
----> 2 with mG:
3 trace2 = pm.load_trace(trace_1)
AttributeError: __enter__
```

I also tried loading like this:

`trace2 = pm.load_trace('.pymc_1.trace', model=mG)`

But the error I get is:

`AttributeError: 'str' object has no attribute 'unobserved_RVs'`

**Anyone know how to do this?**