\[ \int \frac {1}{\sqrt {\tanh ^{-1}(\tanh (a+b x))}} \, dx \]
Optimal antiderivative \[ \frac {2 \sqrt {\arctanh \left (\tanh \left (b x +a \right )\right )}}{b} \]
command
integrate(1/atanh(tanh(b*x+a))**(1/2),x)
Sympy 1.10.1 under Python 3.10.4 output
\[ \begin {cases} \frac {2 \sqrt {\operatorname {atanh}{\left (\tanh {\left (a + b x \right )} \right )}}}{b} & \text {for}\: b \neq 0 \\\frac {x}{\sqrt {\operatorname {atanh}{\left (\tanh {\left (a \right )} \right )}}} & \text {otherwise} \end {cases} \]
Sympy 1.8 under Python 3.8.8 output
\[ \text {Exception raised: TypeError} \]________________________________________________________________________________________