Possible test server dataset description schema error

<xs:simpleType name="casual_string1024">
<!-- Subset on xs:string. Highly restricted form of string. URL-friendly -->
<xs:restriction base="xs:string">
   <xs:pattern value="([a-zA-Z0-9_\-\.(),])+"/>
   <xs:maxLength value="1024"/>
   <xs:minLength value="1"/></xs:restriction>
</xs:simpleType>
<xs:simpleType name="casual_string128">
<!-- Subset on xs:string. Highly restricted form of string. URL-friendly -->
<xs:restriction base="xs:string">
   <xs:pattern value="([a-zA-Z0-9_\-\.(),])+"/>
   <xs:maxLength value="128"/><xs:minLength value="1"/>
   </xs:restriction>
</xs:simpleType>
<xs:simpleType name="casual_string64">
<!-- Subset on xs:string. Highly restricted form of string. URL-friendly -->
<xs:restriction base="xs:string">
   <xs:pattern value="([a-zA-Z0-9_\-\.(),])+"/>
   <xs:maxLength value="64"/>
   <xs:minLength value="1"/>
   </xs:restriction>
</xs:simpleType>

Should the ( and ) be preceded by \ since they are meta-characters used for grouping ?
I am getting a validation error while trying to upload a dataset from scikit-learn.
As an example, the license value 'BSD (from Scikit-learn)' does not pass.

Review the XML schema snippet in the issue and reproduce validation with the license value “BSD (from Scikit-learn)”. Check whether the pattern permits the intended parentheses and determine the schema change needed so valid dataset metadata passes validation. Done means the example license validates without weakening unrelated constraints.