Raise TypeError: 'NoneType' object is not callable when call render_to_png

[satels]

 chart.render_to_png(filename=to_fn)
  File "/usr/local/lib/python3.8/site-packages/pygal/graph/public.py", line 118, in render_to_png
    import cairosvg
  File "/usr/local/lib/python3.8/site-packages/cairosvg/__init__.py", line 42, in <module>
    from . import surface  # noqa isort:skip
  File "/usr/local/lib/python3.8/site-packages/cairosvg/surface.py", line 25, in <module>
    import cairocffi as cairo
  File "/usr/local/lib/python3.8/site-packages/cairocffi/__init__.py", line 48, in <module>
    cairo = dlopen(
  File "/usr/local/lib/python3.8/site-packages/cairocffi/__init__.py", line 30, in dlopen
    library_filename = find_library(library_name)
  File "/usr/local/lib/python3.8/ctypes/util.py", line 311, in find_library
    return _findSoname_ldconfig(name) or \
  File "/usr/local/lib/python3.8/ctypes/util.py", line 276, in _findSoname_ldconfig
    with subprocess.Popen(['/sbin/ldconfig', '-p'],
TypeError: 'NoneType' object is not callable

[satels]

If I move cairosvg importing to global environment that will fix