Graphviz error

[zerth23]

When I run python3 GridAttackSim.py:

Traceback (most recent call last):
  File "GridAttackSim.py", line 16, in <module>
    from graphviz import Source  
  File "/home/user/.local/lib/python3.5/site-packages/graphviz/__init__.py", line 31, in <module>
    from .backend import (DOT_BINARY, UNFLATTEN_BINARY,
  File "/home/user/.local/lib/python3.5/site-packages/graphviz/backend/__init__.py", line 3, in <module>
    from .dot_command import DOT_BINARY
  File "/home/user/.local/lib/python3.5/site-packages/graphviz/backend/dot_command.py", line 39
    cmd = [DOT_BINARY, f'-K{engine}', f'-T{output_format_flag}']

All the dependencies were installed.