What is the meaning of "sure of my claim to be its author" in the following sentences, (Source: PRACTICAL ENGLISH USAGE BY Michael Swan )

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> So many people have helped me to write this revised edition that I am
>  no longer totally **sure of my claim to be its author**.
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Does it mean "So many people have helped me to write this revised edition . Therefore, I don't think of me as its author any more" ?

I try to understand a sentence(=>sure of my claim to be its author) by changing from phrase to clause. Is there anything wrong?

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> **So** many people have helped me to write this revised edition **that** I am no longer totally **sure of my claim to be its author**.
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> =>Many people have helped me to write this revised edition so that I am no longer totally sure that I claim to be its author
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