R: Function to determine if a Matrix is square

I am trying to run this example for the R Programming course on coursEra. However when I try to determine whether or not the matrix is square I get error saying "Error in is.square.matrix(x) : argument x is not a matrix"

My code is below:

##non-square matrix
NCols <- sample(3:6, 1)
NRows <- sample(2:8, 1)

myMat <- matrix(runif(NCols*NRows), ncol=NCols)
is.square.matrix(myMat)

## functions
makeMatrix <- function(x = matrix()) {
  m <- NULL
  set <- function(y) {
    x <<- y
    m <<- NULL
  }
  get <- function() x
  setInv <- if (is.square.matrix(x) == TRUE) {
    function(solve) m <<- solve
  }
     {
    function(ginv) m <<- ginv
  }
  getInv <- function() m
  list(x, set = set, get = get,
       setInv = setInv,
       getInv = getInv)
}

cacheMatrix <- function(x, ...) {
  m <- x$getInv()
  if(!is.null(m)) {
    message("getting cached data")
    return(m)
  }
  data <- x$get()
  m <-  if (is.square.matrix(x) == TRUE) {
    solve(data, ...)
  }
     {
    ginv(data, ...)
  }
  x$setInv(m)
  m
}

## run functions for matrix
notSqaure <- makeMatrix(myMat) 
cacheMatrix(notSqaure)


##check
ginv(myMat)

Then I get the error:

 Error in is.square.matrix(x) : argument x is not a matrix 

I am a beginner so not sure how to get the sentInv to recognize and check if the matrix is square or not.

Brian