Conversion issue using Interpolations

Hello, I have been trying to use **Interpolations.jl** from **Python** but I noticed an issue when **pyjulia** tries to convert the Julia objects back to Python.

I will show you a toy example with what I have been trying to implement:

i ) First I load _Interpolations.jl_ and create the data to be interpolated.

```julia
from julia import Main

Main.using('Interpolations')

Main.h_x = [1, 2, 3, 4]
Main.h_f = [1, 2, 3, 4]

# string to be evaluated along with the extrapolation
interpolation = "interpolate( (h_x, ), h_f, Gridded(Linear()))"
```

ii) Then, there are two ways of running the same code, first like this, creating interpolation object inside the evaluated string:

```
Main.eval(f"h = extrapolate( {interpolation}, Flat())")

Main.eval("typeof(h)")
#

type(Main.h)
#

Main.eval("h(5)")
# 4.0
```

iii) Or, like this, which which creates the object separately from the actual instruction:

```
Main.h2 = Main.eval(f"extrapolate({interpolation}, Flat())")

Main.eval("typeof(h2)")
#

type(Main.h2)
#

Main.eval("h2(1.0)")
# Exception 'MethodError: objects of type Array{Float64,1} are not callable
# Use square brackets [] for indexing an Array.' occurred while calling julia code:
# h2(1.0)
```

Step **ii** works, whereas step **iii** doesn't. So my question is, if this behavior is some kind of bug in pyjulia, although the latter step is used in the pyjulia documentation.

As a corollary, I tried, without luck, to set a parameter to the ```eval("str to eval", get_results=[True|False])``` method to avoid pyjulia from returning Python Objects. The idea behind this is to avoid surplus Jl/Py communications given that I need to run a set of commands in Jl but only use in Py the last result, i.e.,

Run a set of commands in Julia and set get_results=False
* create an interpolation obj
* make some calculations
* make more evaluations

Finally the last command will return a useful value to be used again in Python (get_results=True)
* Get a result and send it back to python

Do you have any suggestion?