Tax Basis for deprecation, but some costs paid in 2nd year?

[Erik Nizenkoff]

Hi,  I purchased a commercial property at the end of December 2017.  I wasn't billed for some of my lawyer's fees and inspection fees until 2018, around $20k.  It is my understanding that I can add these to the basis for depreciation.  How does this work since the fees weren't all paid in the year the purchased closed?  Do I calculate the 2017 depreciation on the week and a half that I owned the property, but not include the fees paid in 2018?  Do the fees paid in 2018 start a new clock and they depreciate in 39 years on their own?  Thanks for any advice!