def nice_find_field(locator)
      begin
        field = find_field(locator)
      rescue Capybara::ElementNotFound
        raise Kelp::FieldNotFound,
          "Could not find field: '#{locator}'"
      end
    end
def nice_find_field(locator)
      begin
        field = find_field(locator)
      rescue Capybara::ElementNotFound
        raise Kelp::FieldNotFound,
          "Could not find field: '#{locator}'"
      end
    end
A slightly friendlier version of Capybara's `find_field`, which actually
 tells you which locator failed to match (instead of giving a useless
 Unable to find '#<XPath::Union:0xXXXXXXX>' message).

 @raise [Kelp::AmbiguousField]
   If more than one field with the given locator was found
 @raise [Kelp::FieldNotFound]
   If no field with the given locator could be found