How to reconstruct a signal from it's Wavelet transform using Mexican Hat wavelet

I have a signal X and I apply a Mexican hat wavelet transform

coefs=cwt(X,0.001:100,'mexh');

Now I want to reconstruct the original signal X but when I try to use the Inverse wavelet transform I can't use the Mexican hat wavelet and the reconstruction is not good enough.

xrec=icwt(coefs,'mexh');

This code throws me the error:

Error using icwt>parseinputs (line 447)
Expected WAVNAME to match one of these values:
'morse', 'bump', 'amor'
The input, 'mexh', did not match any of the valid values.
Error in icwt (line 198)
params = parseinputs(Na,N,sigtype,varargin{:});

Why I cant use the Mexican hat wavelet in the inverse wavelet transform? And how I'm able to use it on the cwt with the 'mexh' if its not an option parameter in the first place?