Expanded class hierarchy of views_handler_field_user_mail

class \views_object
- class \views_handler
  - class \views_handler_area
  - class \views_handler_argument
  - class \views_handler_field
    class \tripal_views_handler_field_sequence
    class \views_handler_field_accesslog_path
    class \views_handler_field_aggregator_category
    class \views_handler_field_aggregator_title_link
    class \views_handler_field_aggregator_xss
    class \views_handler_field_boolean
    class \views_handler_field_broken
    class \views_handler_field_comment
    class \views_handler_field_comment_depth
    class \views_handler_field_comment_username
    class \views_handler_field_contextual_links
    class \views_handler_field_counter
    class \views_handler_field_custom
    class \views_handler_field_date
    class \views_handler_field_entity
    class \views_handler_field_field
    class \views_handler_field_file
    class \views_handler_field_file_extension
    class \views_handler_field_file_size
    class \views_handler_field_file_status
    class \views_handler_field_filter_format_name
    class \views_handler_field_locale_group
    class \views_handler_field_locale_language
    class \views_handler_field_locale_link_edit
    class \views_handler_field_machine_name
    class \views_handler_field_markup
    class \views_handler_field_ncs_last_comment_name
    class \views_handler_field_node
    class \views_handler_field_node_comment
    class \views_handler_field_node_path
    class \views_handler_field_node_translation_link
    class \views_handler_field_numeric
    class \views_handler_field_prerender_list
    class \views_handler_field_residues
    class \views_handler_field_serialized
    class \views_handler_field_taxonomy
    class \views_handler_field_term_link_edit
    class \views_handler_field_time_interval
    class \views_handler_field_url
    class \views_handler_field_user
    class \views_handler_field_user_language
    class \views_handler_field_user_mail
    class \views_handler_field_user_name
    class \views_handler_field_user_link
    class \views_handler_field_user_picture
    class \views_handler_field_xss
  - class \views_handler_filter
  - class \views_handler_relationship
  - class \views_handler_sort
- class \views_plugin