declare a variable as *not* an integer for solve

edit

I am trying to solve symbolically a simple equation for x:

solve(x^K + d == R, x)

I am declaring these variables and assumptions:

var('K, d, R')
assume(K>0)
assume(K, 'real')
assume(R>0)
assume(R<1)

assumptions()
︡> [K > 0, K is real, R > 0, R < 1]

Yet when I run the solve, I obtain the following error:

Error in lines 1-1

Traceback (most recent call last):

File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/smc_sagews/sage_server.py", line 957, in execute exec compile(block+'\n', '', 'single') in namespace, locals

...

File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/sage/interfaces/interface.py", line 671, in __init__ raise TypeError(x)

TypeError: Computation failed since Maxima requested additional constraints; using the 'assume' command before evaluation may help (example of legal syntax is 'assume(K>0)', see assume? for more details)

Is K an integer?

Apparently, maxima is asking whether K is an integer? But I explicitly declared it 'real'! How can I spell out to maxima that it should not assume that K is an integer?

Thanks