FieldStorage details
Behaves like a dictionary:
- .keys(), .has_key() # but not others!
- dictionary-like object ("mapping")
Items
- values are MiniFieldStorage instances
- .value gives field value!
- if multiple values: list of MiniFieldStorage instances
- if type(...) == types.ListType: ...
- may also be FieldStorage instances
- used for file upload (test .file attribute)