Traceback (most recent call last):
  File "main.py", line 3, in <module>
    from solver import Solver
  File "/home/kt/Downloads/kapiszewski/kapiszewski_127296_sztyma_127270/solver.py", line 4, in <module>
    from shard import Shard
  File "/home/kt/Downloads/kapiszewski/kapiszewski_127296_sztyma_127270/shard.py", line 7, in <module>
    from matplotlib import pyplot as plt
  File "/home/kt/Downloads/PiRO1/lib/python3.5/site-packages/matplotlib/pyplot.py", line 2372, in <module>
    switch_backend(rcParams["backend"])
  File "/home/kt/Downloads/PiRO1/lib/python3.5/site-packages/matplotlib/pyplot.py", line 207, in switch_backend
    backend_mod = importlib.import_module(backend_name)
  File "/usr/lib/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/home/kt/Downloads/PiRO1/lib/python3.5/site-packages/matplotlib/backends/backend_tkagg.py", line 1, in <module>
    from . import _backend_tk
  File "/home/kt/Downloads/PiRO1/lib/python3.5/site-packages/matplotlib/backends/_backend_tk.py", line 5, in <module>
    import tkinter as Tk
  File "/usr/lib/python3.5/tkinter/__init__.py", line 38, in <module>
    raise ImportError(str(msg) + ', please install the python3-tk package')
ImportError: No module named '_tkinter', please install the python3-tk package