Single-valued and multi-valued attributes

Specify attributes in this format, with or without spaces on either side of the equal sign:

attribute=value
attribute = value

Attributes can be either single-valued or multi-valued.

Single-valued attributes

Single-valued attributes accept only one value. For single-valued attributes, the syntax is:

attribute = value
attribute = "value with spaces"

Multi-valued attributes

Multi-valued attributes accept one or more values that are separated with spaces and enclosed in braces. Multi-valued attributes can contain a list of values or a value-map.

A list assigns one or more values to the attribute. The syntax is:
```
attribute = {value1 value2 value3}
```
For example: printer-names={printer1 printer2 printer3}
A value-map assigns one value to another. The syntax is:
```
attribute = {value1 -> value2 value3 -> value4}
```
For example: filters={pcl -> pcl2afp.dll pdf -> pdf2afp.dll}