I’m following an example in “Deep Dive on Custom Policy”

<ClaimsTransformations>
<ClaimsTransformation Id="CreateDisplayNameFromFirstNameAndLastName"
TransformationMethod="FormatStringMultipleClaims">
<InputClaims>
<InputClaim ClaimTypeReferenceId="givenName" TransformationClaimType="inputClaim1" />
<InputClaim ClaimTypeReferenceId="surName" TransformationClaimType="inputClaim2" />
</InputClaims>
<InputParameters>
<InputParameter Id="stringFormat" DataType="string" Value="{0} {1}" />
</InputParameters>
<OutputClaims>
<OutputClaim ClaimTypeReferenceId="displayName" TransformationClaimType="outputClaim" />
</OutputClaims>
</ClaimsTransformation>
…
</ClaimsTransformations>

This works fine when givenName and surName are provided. But what if one of is null? The output contains a space. My question is how can I trim this output?

Example:
givenName = null
surName = “Bar”
Output will be ” Bar” (I tested this already)