fix: use global data_quants to handle both old and new pyspedas versions

.gitignore

@@ -1,4 +1,4 @@
 Manifest.toml
 .CondaPkg
-themis_data/thd/l2/fgm/2020/thd_l2_fgm_20200420_v01.cdf
+themis_data
 omni_data

CondaPkg.toml

@@ -1,2 +1,5 @@
+[deps]
+NetCDF4 = ""
+
 [pip.deps]
 pyspedas = "@git+https://github.com/spedas/pyspedas"

src/PySPEDAS.jl

@@ -23,10 +23,17 @@ const TnamesType = Union{AbstractArray, Tuple}
 
 const pyspedas = pynew()
 const pyns = pynew()
+const data_quants = pynew()
 
 function __init__()
     PythonCall.pycopy!(pyspedas, pyimport("pyspedas"))
     PythonCall.pycopy!(pyns, pyimport("numpy").timedelta64(1, "ns"))
+    try
+        PythonCall.pycopy!(data_quants, pyimport("pyspedas.tplot_tools").data_quants)
+    catch
+        # for older versions
+        PythonCall.pycopy!(data_quants, pyimport("pytplot").data_quants)
+    end
     return
 end
 

src/types.jl

@@ -22,7 +22,7 @@ struct TplotVariable{T, N} <: AbstractDataVariable{T, N}
 end
 
 function TplotVariable(name)
-    py = @pyconst(pyimport("pytplot").data_quants)[String(name)]
+    py = data_quants[String(name)]
     data = PyArray(py.data; copy = false)
     return TplotVariable(Symbol(name), data, py)
 end