Get a list of expandable columns from a table input in Power Query

ExpandableColumns.m

expandableColumns = (_) => List.Accumulate(
                           	Table.ColumnNames(_),
                                {},
                                (s,c)=>s&(if Type.Is(Value.Type(Record.Field(_{0},c)), type record)
					or Type.Is(Value.Type(Record.Field(_{0},c)), type list)
					then {c} 
					else {}
                                        )
                              ),
columnHasConsistentType = (T,Cname) =>
				let
				columnTypes = List.Accumulate(Table.Column(T,Cname),
								{},
								(s,c)=>s&{Type.RecordFields(Value.Type(c))})
				in List.Accumulate(columnTypes, 
						true, 
						(s,c)=>s and (columnTypes{0}=c)),