ezdxf.entities.Polyface append_face throw error object of type 'int' has no len()

[machine-w]

import ezdxf
doc = ezdxf.new('R2010')
msp = doc.modelspace()
mesh = msp.add_polyface()

vertices = [
    (0, 0, 0),
    (1, 0, 0),
    (1, 1, 0),
    (0, 1, 0),
    (0, 0, 1),
    (1, 0, 1),
    (1, 1, 1),
    (0, 1, 1),
]
for vertex in vertices:
    mesh.append_vertex(vertex)
faces = [
    [1, 2, 3, 4],  
    [5, 6, 7, 8],  
    [1, 2, 6, 5],  
    [2, 3, 7, 6],  
    [3, 4, 8, 7],  
    [4, 1, 5, 8],  
]
for face in faces:
    mesh.append_face(face)
doc.saveas("polyface_mesh_example.dxf")
print("DXF file created successfully.")
`
throw error ：

`
Traceback (most recent call last):
  File "/Users/machine/myworkspace/oper_dxf/ref/savedxf.py", line 38, in <module>
    mesh.append_face(face)
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/polyline.py", line 610, in append_face
    self.append_faces([face], dxfattribs)
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/polyline.py", line 655, in append_faces
    face_mesh_vertices = self._points_to_dxf_vertices(face, {})
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/polyline.py", line 630, in _points_to_dxf_vertices
    cast("DXFVertex", self._new_compound_entity("VERTEX", dxfattribs))
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/dxfgfx.py", line 630, in _new_compound_entity
    entity = factory.create_db_entry(type_, dxfattribs, self.doc)
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/factory.py", line 63, in create_db_entry
    entity = new(dxftype=dxftype, dxfattribs=dxfattribs)
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/factory.py", line 53, in new
    entity = cls(dxftype).new(
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/dxfentity.py", line 166, in new
    entity.update_dxf_attribs(attribs)
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/dxfentity.py", line 448, in update_dxf_attribs
    setter(key, value)
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/dxfns.py", line 230, in set
    self.__setattr__(key, value)
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/dxfns.py", line 172, in __setattr__
    self.__dict__[key] = check(value)
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/entities/dxfns.py", line 152, in check
    value = cast_value(attrib_def.code, value)
  File "/Users/machine/.pyenv/versions/oper_dxf/lib/python3.10/site-packages/ezdxf/lldxf/types.py", line 435, in cast_value
    return Vec3(value)
  File "src/ezdxf/acc/vector.pyx", line 417, in ezdxf.acc.vector.Vec3.__cinit__
TypeError: object of type 'int' has no len()

[mozman]

You are using the workflow for MESH entities to create PolyFaceMesh entities. This cannot work.

Use the MeshBuilder class to create all mesh-like entities as shown and recommended in these tutorials:

• https://ezdxf.mozman.at/docs/tutorials/polyface.html
• https://ezdxf.mozman.at/docs/tutorials/mesh.html

[mozman]

This is the doc-string of the append_face() method you are using:

"""Append a single face. A `face` is a sequence of (x, y, z) tuples.

Args:
    face: sequence of (x, y, z) tuples
    dxfattribs: dict of DXF attributes for the VERTEX objects

"""