Visual Paradigm: Invalid Syntax Highlighting without acutal syntax mistake (as far as I can see)

I think I have encountered an error message that is not necessarily valid or helpful. If it is valid, please tell me what the mistake I encounter is triggered by.

You do not follows UML notation and you exchanged the parameter and its type, your operations must be

• create(entity : E) : Result<E>
• create(entities : iterable<E>) : ResultCollection<E>

Your create(E : entity) : Result<E> was accepted 'syntactically' because the var can be E and its type entity, but in the second case the var name iterable<E> is illegal and the tool refuses that.

From formal/2017-12-05 §9.6.4 page 117 and 118 :

If shown in a diagram, an Operation is shown as a text string of the form:

[<visibility>] <name> ‘(‘ [<parameter-list>] ‘)’
      [‘:’ [<return-type>] [‘[‘ <multiplicity-range> ‘]’]
      [‘{‘ <oper-property> [‘,’ <oper-property>]* ‘}’]]

and <parameter-list> is a list of Parameters of the Operation in the following format:

<parameter-list> ::= <parameter> [‘,’<parameter>]*

and § 9.4.4 page 110 :

<parameter> ::= [<direction>] <parameter-name> ’:’ <type-expression>
     [’[’<multiplicity-range>’]’] [’=’ <default>]
     [’{’ <parm-property> [’,’ <parm-property>]* ’}’]

So it must be <parameter-name> ’:’ <type-expression> rather than <type-expression> ’:’ <parameter-name> as you did