@pimms.require<EOL><INDENT>def validate_properties(vertex_count, _properties):<DEDENT>
if _properties is None or len(_properties.column_names) == <NUM_LIT:0>:<EOL><INDENT>return True<EOL><DEDENT>if vertex_count != _properties.row_count:<EOL><INDENT>ns = (_properties.row_count, vertex_count)<EOL>raise ValueError('<STR_LIT>' % ns)<EOL><DEDENT>return True<EOL>
tess.validate_properties requres that all non-builtin properties have the same number of
  entries as the there are vertices in the tesselation.