code: def paragraph(style=nil)
           node = ParagraphNode.new(self, style)
           yield node if block_given?
           self.store(node)
        end
docs: This method provides a short cut means of creating a paragraph command
   node. The method accepts a block that will be passed a single parameter
   which will be a reference to the paragraph node created. After the
   block is complete the paragraph node is appended to the end of the child
   nodes on the object that the method is called against.
  
   ==== Parameters
   style::  A reference to a ParagraphStyle object that defines the style
            for the new paragraph. Defaults to nil to indicate that the
            currently applied paragraph styling should be used.