docs: def fromInputs(self, inputs):
          """
          Extract the inputs associated with this parameter from the given
          dictionary and coerce them using C{self.coercer}.
  
          @type inputs: C{dict} mapping C{str} to C{list} of C{str}
          @param inputs: The contents of a form post, in the conventional
              structure.
  
          @rtype: L{Deferred}
          @return: A Deferred which will be called back with a list of the
              structured data associated with this parameter.
          """
          outputs = []
          for i in xrange(self.count):
              name = self.name + '_' + str(i)
              try:
                  value = inputs[name][0]
              except KeyError:
                  raise ConfigurationError(
                      "Missing value for field %d of %s" % (i, self.name))
              else:
                  outputs.append(maybeDeferred(self.coercer, value))
          return gatherResults(outputs)