Whats wrong with my code?

def square(n):

"""Returns the square of a number."""

squared = n**2

print "%d squared is %d." % (n, squared)

return squared

def square(10):

squared = 10**2

print "%d squared is %d." % (10, squared)

return squared

It just comes up with a syntax error can anyone help?

"""Returns the square of a number."""

squared = n**2

print "%d squared is %d." % (n, squared)

return squared

def square(10):

squared = 10**2

print "%d squared is %d." % (10, squared)

return squared

It just comes up with a syntax error can anyone help?