“使用PyPlot”导致Windows 10上的Julia 1.0.0错误：“ pyimport无法找到Python软件包matplotlib。 ”

Julia 1.0.0 on Windows 10 error from 'using PyPlot': “The Python package matplotlib could not be found by pyimport. ”

刚刚从julialang.org安装了Julia 1.0.0
做了以下事情：

using Pkg

Pkg.add(" PyPlot")
使用PyPlot

。。。得到这个错误：
pyimport找不到Python软件包matplotlib。通常，这意味着您没有在PyCall使用的Python版本中安装matplotlib。

我已经安装了Python。

JULIA 1.0.0日志已满...………

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

_
_ _ _(_)_ | Documentation: https://docs.julialang.org
(_) | (_) (_) |
_ _ _| |_ __ _ | Type"?" for help,"]?" for Pkg help.
| | | | | | |/ _` | |
| | |_| | | | (_| | | Version 1.0.0 (2018-08-08)
_/ |\__'_|_|_|\__'_| | Official https://julialang.org/ release
|__/ |

julia> using Pkg

julia> Pkg.add("PyPlot")
Updating registry at `C:\Users\douglaskbell\.julia
egistries\General`
Updating git-repo `https://github.com/JuliaRegistries/General.git`
Resolving package versions...
Updating `C:\Users\douglaskbell\.julia\environments\v1.0\Project.toml`
[no changes]
Updating `C:\Users\douglaskbell\.julia\environments\v1.0\Manifest.toml`
[no changes]

julia> using PyPlot
[ Info: Installing matplotlib via the Conda matplotlib package...
[ Info: Running `conda install -y matplotlib` in root environment
Solving environment: done

# All requested packages already installed.

ERROR: InitError: PyError (PyImport_ImportModule

The Python package matplotlib could not be found by pyimport. Usually this means
that you did not install matplotlib in the Python version being used by PyCall.