ValueError("color kwarg must have one color per dataset")?
This problem is because you have defined tfirst_list as a N-dimensional array.
For example:
tfirst_list = [1, 2, 3, 4, 5, 6, 7, 8] #works
tfirst_list = [[1, 2, 3, 4], [5, 6, 7, 8]] #produces the Exception you have
If you are using N-dimensional data (N datasets), then the color
keyword argument (color kwarg) must be also N-dimensional (one color per dataset). For example for the case above:
color = ['b', 'r']