<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def validate_context_for_visiting_vertex_field(parent_location, vertex_field_name, context):
 """Ensure that the current context allows for visiting a vertex field."""

    if is_in_fold_innermost_scope(context):
        raise GraphQLCompilationError(
            u'Traversing inside a @fold block after filtering on {} or outputting fields '
            u'is not supported! Parent location: {}, vertex field name: {}'
            .format(COUNT_META_FIELD_NAME, parent_location, vertex_field_name))